Annina Ropponen - Academia.edu (original) (raw)

Papers by Annina Ropponen

Research paper thumbnail of Author’s response to reviews Title: Health, work and demographic factors associated with a lower risk of work disability and unemployment in employees with lower back, neck and shoulder pain Authors

Research paper thumbnail of Sustainable Working Life in a Swedish Twin Cohort—A Definition Paper with Sample Overview

International Journal of Environmental Research and Public Health, 2021

Background: A unified or consensus definition of “sustainable working life” remains lacking, alth... more Background: A unified or consensus definition of “sustainable working life” remains lacking, although studies investigating risk factors for labour market exit are numerous. In this study, we aimed (1) to update the information and to explore a definition of “sustainable working life” via a systematic literature review and (2) to describe the working life trajectories via the prevalence of sickness absence (SA), disability pension (DP), and unemployment in a Swedish twin cohort to provide a sample overview in our Sustainable Working Life-project. Methods: A systematic literature review was conducted to explore the studies with the search phrase “sustainable working life” in PubMed, PsycInfo, and the Web of Science Database of Social Sciences in January 2021, resulting in a total of 51 references. A qualitative synthesis was performed for the definitions and the measures of “sustainable working life.” Based on the Swedish Twin project Of Disability pension and Sickness absence (STODS...

Research paper thumbnail of Life events as predictors for disability pension due to musculoskeletal diagnoses: a cohort study of Finnish twins

International Archives of Occupational and Environmental Health, 2019

Purpose Musculoskeletal diagnoses (MSD) are one of the largest diagnostic groups for disability p... more Purpose Musculoskeletal diagnoses (MSD) are one of the largest diagnostic groups for disability pensions (DP). This study investigated the associations between life events and DP due to MSD, considering sociodemographic, health, and familial factors. Methods The study sample included 18,530 Finnish twins, 24–64 years old at baseline, who responded to a questionnaire in 1981 including a 21-item life event inventory. Information on DP with diagnosis codes (ICD codes: M00–M99) were obtained from the official national pension registers. Life events were divided into family- and work-related events. “Positive change in life” was analyzed separately. Cox proportional hazards models were used to calculate hazard ratios (HR) with 95% confidence intervals (CI). Results During the follow-up of 23 years, 1273 (7%) individuals were granted DP due to MSD. In discordant pair analysis, family-related events (≥ 4 events) increased (HR 1.63, 95% CI 1.31, 2.03) and the absence of such events decrease...

Research paper thumbnail of Night work as a risk factor for future cause-specific disability pension: A prospective twin cohort study in Sweden

Chronobiology international, 2018

The objectives of the study were to investigate the associations between night work and disabilit... more The objectives of the study were to investigate the associations between night work and disability pension (DP) due to all causes, cardiovascular (CVD), mental, and other diagnoses, adjusting for familial confounding. The material of the study included comprehensive survey data on 27 165 Swedish twins born in 1935-1958 that were linked with DP data for the survey period (1998-2003) to 2013. Night work was assessed as years of working nights at least every now and then, and categorized into not at all, 1-10 years and over 10 years. For statistical analyses, Cox proportional hazards regressions were used to calculate hazard ratios (HRs) with 95% confidence intervals (CIs). The results of the study indicated that over 10 years duration of night work had an age- and sex-adjusted HR of 1.48 (95% CI 1.11-1.98) for DP due to CVD and 1-10 years of night work an HR of 1.28 (95% CI 1.06-1.55) for DP due to mental diagnoses, but attenuated when covariates were adjusted for. Both 1-10 years (HR...

Research paper thumbnail of Night work as a risk factor of future disability pension due to musculoskeletal diagnoses: a prospective cohort study of Swedish twins

European Journal of Public Health, 2017

Background: This study investigated the associations between night work, sleep and disability pen... more Background: This study investigated the associations between night work, sleep and disability pension (DP) due to musculoskeletal disorders (MSD), while controlling for several confounding factors including both genetic factors and shared family background. Methods: The study sample consisted of 27 165 Swedish twin individuals born in 1935-58 with comprehensive survey data on sociodemographic, health and lifestyle factors. Night work was assessed as years of working hours at night at least every now and then, and categorized into 'not at all, 1-10 years and over 10 years'. Data on DP with MSD (ICD-diagnoses M00-M99) were obtained from the National Social Insurance Agency. Follow-up was from the time of the interview in 1998-2003 until 2013. Information on the length and quality of sleep was available for a sub-sample of twins (n = 1684). Cox proportional hazards models were used to calculate hazard ratios (HR) with 95% confidence intervals (CI). Results: During the follow-up, 1338 (5%) participants were granted DP due to MSD. Both 1-10 years (HR 1.33, 95% CI 1.17-1.53) and over 10 years of night work (HR 1.39 95% CI 1.18-1.64) increased the risk of future DP. The associations were not affected by health, lifestyle or sleep factors. In the discordant twin pair analysis, the associations between night work and DP due to MSD attenuated. Conclusions: Night work was associated with increased risk of DP due to MSD independently from health and lifestyle factors. Familial confounding could not be ruled out.

Research paper thumbnail of Association between long-term smoking and leisure-time physical inactivity: a cohort study among Finnish twins with a 35-year follow-up

International Journal of Public Health, 2017

Research paper thumbnail of Association between education and future leisure-time physical inactivity: a study of Finnish twins over a 35-year follow-up

BMC public health, Aug 4, 2016

Education is associated with health related lifestyle choices including leisure-time physical ina... more Education is associated with health related lifestyle choices including leisure-time physical inactivity. However, the longitudinal associations between education and inactivity merit further studies. We investigated the association between education and leisure-time physical inactivity over a 35-year follow-up with four time points controlling for multiple covariates including familial confounding. This study of the population-based Finnish Twin Cohort consisted of 5254 twin individuals born in 1945-1957 (59 % women), of which 1604 were complete same-sexed twin pairs. Data on leisure-time physical activity and multiple covariates was available from four surveys conducted in 1975, 1981, 1990 and 2011 (response rates 72 to 89 %). The association between years of education and leisure-time physical inactivity (<1.5 metabolic equivalent hours/day) was first analysed for each survey. Then, the role of education was investigated for 15-year and 35-year inactivity periods in the longit...

Research paper thumbnail of Stability and change of body mass index as a predictor of disability pension

Scandinavian journal of public health, 2016

To investigate whether stability or change in body mass index (BMI) predict disability pension (D... more To investigate whether stability or change in body mass index (BMI) predict disability pension (DP) due to musculoskeletal diagnosis (MSD) when controlling for familial confounding. Our study cohort consisted of 17,169 Finnish twins born before 1958. Data on BMI and multiple covariates from questionnaires in 1975 and 1981 were included and DPs were collected from the national pension registers until the end of 2004. Cox proportional hazards regression models with Hazard Ratios (HR) and 95% Confidence Intervals (CI) were used for statistical analyses. General DP was granted to 2853 individuals and DP due to MSD to 1143 individuals during the 23-year follow-up. A one-unit increase in BMI in both 1975 (HR 1.08, 95% CI 1.05, 1.10) and 1981 (HR 1.06, 95% CI 1.04, 1.07), as well as the stability of and change in BMI from 1975 to 1981 were all associated with an increased risk of DP. These associations held in the analyses controlling for multiple covariates (age, sex, socioeconomic status...

Research paper thumbnail of Leisure-time physical inactivity and association with body mass index: a Finnish Twin Study with a 35-year follow-up

International journal of epidemiology, Feb 15, 2016

We investigated the stability and change of leisure-time physical inactivity in adult men and wom... more We investigated the stability and change of leisure-time physical inactivity in adult men and women during a 35-year follow-up. We also analysed the impact of long-term physical inactivity on the development of body mass index (BMI). In this population-based cohort study, 5254 Finnish twin individuals (59% women) participated in four surveys in 1975, 1981, 1990 and 2011. Mean age at baseline was 23.9 years. Individual long-term leisure-time physical activity (LTPA) was categorized into seven classes varying from 'persistently inactive' to 'persistently active'. We used the multivariate multilevel mixed-effects linear regression model and paired-sample t-test in the analyses. Co-twin control design was used for examining within-pair associations. Of men 11%, and of women 8%, were persistently inactive. Among both sexes, the mean BMI slope trajectories were steeper among the persistently inactive and those who became inactive than among those who were persistently acti...

Research paper thumbnail of Genetic and Environmental Influences on Disability Pension Due To Mental Diagnoses: Limited Importance of Major Depression, Generalized Anxiety, and Chronic Fatigue

Twin Research and Human Genetics, 2015

Background:Previous research indicates that liability to disability pension (DP) due to mental di... more Background:Previous research indicates that liability to disability pension (DP) due to mental diagnoses is moderately influenced by genetic factors. This study investigates whether genetic contributions to the liability to DP due to mood and neurotic diagnoses overlap with the genetic influences on major depression (MD), generalized anxiety disorder (GAD), or chronic fatigue (CF).Method:A prospective cohort study including 9,985 female twins born in Sweden 1933–1958. The presence of MD, GAD, and CF was assessed by computer-assisted telephone interviews conducted in 1998–2002. Data on DP due to mood and neurotic diagnoses were obtained from nationwide registers for the years 1998–2010. Common genetic and environmental influences on the phenotypes were estimated by applying structural equation modeling.Results:The prevalence of MD/GAD was 30%, CF 8%, and DP due to mood and neurotic diagnoses 3% in 2010. Genetic effects on MD/GAD explained 31% of the total genetic variation in DP, whe...

Research paper thumbnail of Occurrence of sickness absence and disability pension in relation to childbirth: A 16-year follow-up study of 6323 Swedish twins

Scandinavian journal of public health, Jan 12, 2015

Pregnancy, delivery, and the postpartum period may imply morbidity leading to work incapacity; ho... more Pregnancy, delivery, and the postpartum period may imply morbidity leading to work incapacity; however, this is seldom studied. This study aimed to compare twin sisters giving or not giving birth regarding occurrence of sickness absence (SA) and disability pension (DP). This population-based cohort study included all 6323 female twins born in Sweden 1959-1990, using register data for 1994-2010 about SA and DP. Average number of SA/DP days/year was calculated in relation to the year of the first delivery, or, if not giving birth, the year when the twin sister gave birth. Twin pairs discordant for delivery were used to investigate the importance of genetic and environmental factors for occurrence of SA and DP. In all, 52% had a first delivery during 1994-2010. Except for the year of delivery, the average number of SA days/year was similar when comparing women who gave birth to those who did not, while number of DP days was significantly higher in women who did not give birth. Differen...

Research paper thumbnail of Associations between Childbirth, Hospitalization and Disability Pension: A Cohort Study of Female Twins

PLoS ONE, 2014

Background: As the literature on long-term effects of childbirth on risk of morbidity or permanen... more Background: As the literature on long-term effects of childbirth on risk of morbidity or permanent work incapacity (DP) is limited, we aimed to study associations of childbirth with hospitalization and DP, adjusting for familial factors. Methods: This cohort study included female twins, i.e. women with twin sister, born 1959-1990 in Sweden (n = 5 118). At least one in the twin pair had their first childbirth 1994-2009. Women were followed regarding all-cause and cause-specific (mental or musculoskeletal diagnoses) DP during year 2-5 after first delivery or equivalent. Associations between childbirth, hospitalization and DP were calculated as hazard ratios (HR) with 95% confidence intervals (CI). Results: Women who did not give birth had markedly higher number of DP days/year compared to those giving birth. Hospitalization after first childbirth was associated with a higher HR of DP. Those hospitalized at least once after their first childbirth had a threefold DP risk (HR: 3.2; 95% CI 1.1-9.6), DP due to mental diagnoses (HR: 3.2; 1.2-8.8), and of DP due to musculoskeletal diagnoses (HR: 6.1; 1.6-22.9). Lower HRs in the discordant twin pair analyses indicated that familial factors may influence the studied associations. Conclusions: Women who did not give birth had a much higher risk for DP than those who did. Among those who gave birth, the risk for DP was markedly higher among those with a previous hospitalization, and especially in women with repeated hospitalizations. The results indicate a health selection into giving birth as well as the importance of morbidity for DP.

Research paper thumbnail of Incidence of disability pension and associations with socio-demographic factors in a Swedish twin cohort

Social Psychiatry and Psychiatric Epidemiology, 2012

Research paper thumbnail of Sleep Patterns as Predictors for Disability Pension Due to Low Back Diagnoses: A 23-Year Longitudinal Study of Finnish Twins

SLEEP, 2013

Impaired sleep patterns are known to be associated with many chronic conditions and ultimately th... more Impaired sleep patterns are known to be associated with many chronic conditions and ultimately they may lead to permanent work incapacity. Less is known about the associations between sleep patterns and cause-specific disability pensions, such as low back diagnoses, or whether familial factors (genetics and family environment) can affect the associations. The objective of this study was to investigate sleep patterns as predictors of disability pension due to low back diagnoses with a 23-year follow-up. Design and Setting: A prospective cohort study with comprehensive mailed questionnaires about sleep patterns, e.g., quality and length of sleep in 1975 and 1981. Follow-up from the national disability pension register data until 2004. Interventions: Not applicable. Participants: There were 18,979 individuals (7,722 complete twin pairs) born before 1958. Measurements and Results: Cox proportional hazards regression was used to calculate hazard ratios (HR) with 95% confidence intervals (95% CI). Disability pension due to low back diagnoses had been granted to 467 individuals during the follow-up. Sleeping moderately well (HR 1.25; 95% CI 1.02, 1.53), or fairly poorly/poorly (HR 2.05; 95% CI 1.53, 2.73) at baseline predicted a significantly higher risk for disability pension. Stable patterns of sleeping either fairly well (HR 1.29; 95% CI 1.01, 1.64), or stably fairly poorly/poorly (HR 2.29; 95% CI 1.49, 3.52) between 1975 and 1981 were associated with a higher risk as compared to a stable pattern of sleeping well. Furthermore, a decrease in quality of sleep from 1975 to 1981 was associated (HR 1.34; 95% CI 1.03, 1.76) with an increased risk of disability pension. Conclusions: Sleep quality and changes in sleep quality appear to be early predictors for disability pension due to low back diagnoses independently from other confounding factors.

Research paper thumbnail of Disability pension due to musculoskeletal diagnoses: importance of work-related factors in a prospective cohort study of Finnish twins

Scandinavian Journal of Work, Environment & Health, 2013

Several work-related risk factors, such as physical workload and stress, are independent, direct ... more Several work-related risk factors, such as physical workload and stress, are independent, direct risk factors for disability pension due to musculoskeletal diagnosis, not affected by familial factors. Identification of these risk factors during a person's lifespan would be beneficial for occupational health care and individuals to reduce permanent work incapacity due to musculoskeletal diagnosis.

Research paper thumbnail of Psychosocial working conditions, occupational groups, and risk of disability pension due to mental diagnoses: a cohort study of 43 000 Swedish twins

Scandinavian Journal of Work, Environment & Health, 2012

Psychosocial working conditions, occupational groups, and risk of disability pension due to menta... more Psychosocial working conditions, occupational groups, and risk of disability pension due to mental diagnoses: a cohort study of 43 000 Swedish twins by Samuelsson Å, Ropponen A, Alexanderson K, Svedberg P Use of twin data made it possible to account for familial confounding to the associations between psychosocial working conditions and disability pension due to mental diagnoses. After accounting for familial confounding, the associations between job demands, job control, and disability pension due to mental diagnoses remained, suggesting that these factors are independent predictors of disability pension with mental diagnoses.

Research paper thumbnail of Physical work load and psychological stress of daily activities as predictors of disability pension due to musculoskeletal disorders

Scandinavian Journal of Public Health, 2014

Aims: Physical work loading and psychological stress commonly co-occur in working life, hence pot... more Aims: Physical work loading and psychological stress commonly co-occur in working life, hence potentially having an interrelationship that may affect work incapacity. This prospective cohort study aimed to investigate the effect of stability and change in physical work loading and stress on the risk of disability pension (DP) due to musculoskeletal diagnoses (MSD), while accounting for familial confounding in these associations. Methods: Data on 12,455 twins born before 1958 were surveyed of their physical work loading and psychological stress of daily activities in 1975 and 1981. The follow-up data was collected from pension registers until 2004. Cox proportional hazards regression models were used. Results: During the follow up, 893 participants were granted DP due to MSD. Stable high (hazard ratio, HR, 2.21), but also increased physical work loading (HR 2.05) and high psychological stress (HR 2.22) were associated with increased risk for DP, and had significant interaction ( p=0....

Research paper thumbnail of Health-related risk factors for disability pensions due to musculoskeletal diagnoses: A 30-year Finnish twin cohort study

Scandinavian Journal of Public Health, 2011

Aims: There is a need to better understand work incapacity due to musculoskeletal disorders (MSD)... more Aims: There is a need to better understand work incapacity due to musculoskeletal disorders (MSD) and the factors that contribute to being granted disability pension (DP) with such disorders. A twin cohort study would serve a powerful tool responding to this knowledge gap by providing information on factors affecting DP when controlling for family background. The purpose was to investigate the incidence of and risk factors for DP due to any MSD ( n = 1,819) and specifically due to osteoarthritis (OA, n = 677) in a twin cohort of 24,043 people over a 30-year follow-up. Methods: Data on twin pairs from a mailed questionnaire during the baseline year of 1975 were followed up with register data regarding DP, emigration, old-age pension, and death. For statistical analysis, univariate and multivariate Cox proportional hazard ratios were estimated. Results: Baseline musculoskeletal pain, frequency of use of analgesics, body mass index, and chronic diseases, as well as education and social...

Research paper thumbnail of Persistent smoking as a predictor of disability pension due to musculoskeletal diagnoses: A 23year prospective study of Finnish twins

Preventive Medicine, 2013

To investigate whether stability or changes in smoking predict disability pension (DP) due to low... more To investigate whether stability or changes in smoking predict disability pension (DP) due to low back diagnoses (LBD) and musculoskeletal diagnoses (MSD) after taking familial confounding into account using a co-twin design. Longitudinal smoking patterns and multiple covariates in a population-based cohort of 17,451 Finnish twins (6959 complete pairs) born before 1958 were surveyed through questionnaires in 1975 and 1981. The outcome data were collected from the national pension registers until the end of 2004. Cox proportional hazards regression models were used for statistical analyses. Disability pension due to low back diagnoses was granted to 408 individuals and disability pension due to musculoskeletal diagnoses to 1177 individuals during the follow-up of 23 years. Being a persistent smoker (current smoker both 1975 and 1981) predicted a significantly increased risk for disability pension (hazard ratio 1.69, 95% confidence interval 1.46, 1.97) compared to those individuals who had never smoked. The association remained when several confounding factors, including familial factors, were taken into account. Persistent smoking predicts early disability pension due to musculoskeletal diagnoses and low back diagnoses independently from numerous confounding factors, including familial effects shared by the co-twins.

Research paper thumbnail of A prospective twin cohort study of disability pensions due to musculoskeletal diagnoses in relation to stability and change in pain

PAIN, 2013

Pain is known to play an important role in the pathway to becoming work disabled, in particular f... more Pain is known to play an important role in the pathway to becoming work disabled, in particular for award of disability pensions (DP) due to musculoskeletal diagnoses (MSD). This prospective cohort study investigated MSD-related pain stability and/or changes as predictors for DP during a 23-year follow-up. Additionally confounding factors were examined to elucidate whether familial effects (including genetics and family background) or socioeconomic status, other pain, or use of medication would affect the associations between pain and DP. Data were available on 11,224 twins (4399 complete pairs) born before 1958 surveyed through questionnaires about background factors and musculoskeletal (low back, neck, and shoulder) pain impairing work ability in 1975 and 1981. The follow-up data were collected from pension registers until 2004. Cox proportional hazards regression models were used. During the 23-year follow-up, 508 DPs due to MSD, 166 DPs due to osteoarthritis (OA), and 162 DPs due to low back diagnoses (LBD) were granted. Musculoskeletal pain impairing work ability both measured at 1 time point and 6 years apart, and either 1 pain location or multiple locations, predicted increased risk for DP due to MSD, OA, and LBD. The associations were independent of familial confounding factors and of several influential background factors, including headache; migraine; use of analgesics, hypnotics, or tranquillizers; life satisfaction; and education and marital status. This study concluded that musculoskeletal pain impairing work ability is an early and direct predictor for DP due to MSD, OA, and LBD.

Research paper thumbnail of Author’s response to reviews Title: Health, work and demographic factors associated with a lower risk of work disability and unemployment in employees with lower back, neck and shoulder pain Authors

Research paper thumbnail of Sustainable Working Life in a Swedish Twin Cohort—A Definition Paper with Sample Overview

International Journal of Environmental Research and Public Health, 2021

Background: A unified or consensus definition of “sustainable working life” remains lacking, alth... more Background: A unified or consensus definition of “sustainable working life” remains lacking, although studies investigating risk factors for labour market exit are numerous. In this study, we aimed (1) to update the information and to explore a definition of “sustainable working life” via a systematic literature review and (2) to describe the working life trajectories via the prevalence of sickness absence (SA), disability pension (DP), and unemployment in a Swedish twin cohort to provide a sample overview in our Sustainable Working Life-project. Methods: A systematic literature review was conducted to explore the studies with the search phrase “sustainable working life” in PubMed, PsycInfo, and the Web of Science Database of Social Sciences in January 2021, resulting in a total of 51 references. A qualitative synthesis was performed for the definitions and the measures of “sustainable working life.” Based on the Swedish Twin project Of Disability pension and Sickness absence (STODS...

Research paper thumbnail of Life events as predictors for disability pension due to musculoskeletal diagnoses: a cohort study of Finnish twins

International Archives of Occupational and Environmental Health, 2019

Purpose Musculoskeletal diagnoses (MSD) are one of the largest diagnostic groups for disability p... more Purpose Musculoskeletal diagnoses (MSD) are one of the largest diagnostic groups for disability pensions (DP). This study investigated the associations between life events and DP due to MSD, considering sociodemographic, health, and familial factors. Methods The study sample included 18,530 Finnish twins, 24–64 years old at baseline, who responded to a questionnaire in 1981 including a 21-item life event inventory. Information on DP with diagnosis codes (ICD codes: M00–M99) were obtained from the official national pension registers. Life events were divided into family- and work-related events. “Positive change in life” was analyzed separately. Cox proportional hazards models were used to calculate hazard ratios (HR) with 95% confidence intervals (CI). Results During the follow-up of 23 years, 1273 (7%) individuals were granted DP due to MSD. In discordant pair analysis, family-related events (≥ 4 events) increased (HR 1.63, 95% CI 1.31, 2.03) and the absence of such events decrease...

Research paper thumbnail of Night work as a risk factor for future cause-specific disability pension: A prospective twin cohort study in Sweden

Chronobiology international, 2018

The objectives of the study were to investigate the associations between night work and disabilit... more The objectives of the study were to investigate the associations between night work and disability pension (DP) due to all causes, cardiovascular (CVD), mental, and other diagnoses, adjusting for familial confounding. The material of the study included comprehensive survey data on 27 165 Swedish twins born in 1935-1958 that were linked with DP data for the survey period (1998-2003) to 2013. Night work was assessed as years of working nights at least every now and then, and categorized into not at all, 1-10 years and over 10 years. For statistical analyses, Cox proportional hazards regressions were used to calculate hazard ratios (HRs) with 95% confidence intervals (CIs). The results of the study indicated that over 10 years duration of night work had an age- and sex-adjusted HR of 1.48 (95% CI 1.11-1.98) for DP due to CVD and 1-10 years of night work an HR of 1.28 (95% CI 1.06-1.55) for DP due to mental diagnoses, but attenuated when covariates were adjusted for. Both 1-10 years (HR...

Research paper thumbnail of Night work as a risk factor of future disability pension due to musculoskeletal diagnoses: a prospective cohort study of Swedish twins

European Journal of Public Health, 2017

Background: This study investigated the associations between night work, sleep and disability pen... more Background: This study investigated the associations between night work, sleep and disability pension (DP) due to musculoskeletal disorders (MSD), while controlling for several confounding factors including both genetic factors and shared family background. Methods: The study sample consisted of 27 165 Swedish twin individuals born in 1935-58 with comprehensive survey data on sociodemographic, health and lifestyle factors. Night work was assessed as years of working hours at night at least every now and then, and categorized into 'not at all, 1-10 years and over 10 years'. Data on DP with MSD (ICD-diagnoses M00-M99) were obtained from the National Social Insurance Agency. Follow-up was from the time of the interview in 1998-2003 until 2013. Information on the length and quality of sleep was available for a sub-sample of twins (n = 1684). Cox proportional hazards models were used to calculate hazard ratios (HR) with 95% confidence intervals (CI). Results: During the follow-up, 1338 (5%) participants were granted DP due to MSD. Both 1-10 years (HR 1.33, 95% CI 1.17-1.53) and over 10 years of night work (HR 1.39 95% CI 1.18-1.64) increased the risk of future DP. The associations were not affected by health, lifestyle or sleep factors. In the discordant twin pair analysis, the associations between night work and DP due to MSD attenuated. Conclusions: Night work was associated with increased risk of DP due to MSD independently from health and lifestyle factors. Familial confounding could not be ruled out.

Research paper thumbnail of Association between long-term smoking and leisure-time physical inactivity: a cohort study among Finnish twins with a 35-year follow-up

International Journal of Public Health, 2017

Research paper thumbnail of Association between education and future leisure-time physical inactivity: a study of Finnish twins over a 35-year follow-up

BMC public health, Aug 4, 2016

Education is associated with health related lifestyle choices including leisure-time physical ina... more Education is associated with health related lifestyle choices including leisure-time physical inactivity. However, the longitudinal associations between education and inactivity merit further studies. We investigated the association between education and leisure-time physical inactivity over a 35-year follow-up with four time points controlling for multiple covariates including familial confounding. This study of the population-based Finnish Twin Cohort consisted of 5254 twin individuals born in 1945-1957 (59 % women), of which 1604 were complete same-sexed twin pairs. Data on leisure-time physical activity and multiple covariates was available from four surveys conducted in 1975, 1981, 1990 and 2011 (response rates 72 to 89 %). The association between years of education and leisure-time physical inactivity (<1.5 metabolic equivalent hours/day) was first analysed for each survey. Then, the role of education was investigated for 15-year and 35-year inactivity periods in the longit...

Research paper thumbnail of Stability and change of body mass index as a predictor of disability pension

Scandinavian journal of public health, 2016

To investigate whether stability or change in body mass index (BMI) predict disability pension (D... more To investigate whether stability or change in body mass index (BMI) predict disability pension (DP) due to musculoskeletal diagnosis (MSD) when controlling for familial confounding. Our study cohort consisted of 17,169 Finnish twins born before 1958. Data on BMI and multiple covariates from questionnaires in 1975 and 1981 were included and DPs were collected from the national pension registers until the end of 2004. Cox proportional hazards regression models with Hazard Ratios (HR) and 95% Confidence Intervals (CI) were used for statistical analyses. General DP was granted to 2853 individuals and DP due to MSD to 1143 individuals during the 23-year follow-up. A one-unit increase in BMI in both 1975 (HR 1.08, 95% CI 1.05, 1.10) and 1981 (HR 1.06, 95% CI 1.04, 1.07), as well as the stability of and change in BMI from 1975 to 1981 were all associated with an increased risk of DP. These associations held in the analyses controlling for multiple covariates (age, sex, socioeconomic status...

Research paper thumbnail of Leisure-time physical inactivity and association with body mass index: a Finnish Twin Study with a 35-year follow-up

International journal of epidemiology, Feb 15, 2016

We investigated the stability and change of leisure-time physical inactivity in adult men and wom... more We investigated the stability and change of leisure-time physical inactivity in adult men and women during a 35-year follow-up. We also analysed the impact of long-term physical inactivity on the development of body mass index (BMI). In this population-based cohort study, 5254 Finnish twin individuals (59% women) participated in four surveys in 1975, 1981, 1990 and 2011. Mean age at baseline was 23.9 years. Individual long-term leisure-time physical activity (LTPA) was categorized into seven classes varying from 'persistently inactive' to 'persistently active'. We used the multivariate multilevel mixed-effects linear regression model and paired-sample t-test in the analyses. Co-twin control design was used for examining within-pair associations. Of men 11%, and of women 8%, were persistently inactive. Among both sexes, the mean BMI slope trajectories were steeper among the persistently inactive and those who became inactive than among those who were persistently acti...

Research paper thumbnail of Genetic and Environmental Influences on Disability Pension Due To Mental Diagnoses: Limited Importance of Major Depression, Generalized Anxiety, and Chronic Fatigue

Twin Research and Human Genetics, 2015

Background:Previous research indicates that liability to disability pension (DP) due to mental di... more Background:Previous research indicates that liability to disability pension (DP) due to mental diagnoses is moderately influenced by genetic factors. This study investigates whether genetic contributions to the liability to DP due to mood and neurotic diagnoses overlap with the genetic influences on major depression (MD), generalized anxiety disorder (GAD), or chronic fatigue (CF).Method:A prospective cohort study including 9,985 female twins born in Sweden 1933–1958. The presence of MD, GAD, and CF was assessed by computer-assisted telephone interviews conducted in 1998–2002. Data on DP due to mood and neurotic diagnoses were obtained from nationwide registers for the years 1998–2010. Common genetic and environmental influences on the phenotypes were estimated by applying structural equation modeling.Results:The prevalence of MD/GAD was 30%, CF 8%, and DP due to mood and neurotic diagnoses 3% in 2010. Genetic effects on MD/GAD explained 31% of the total genetic variation in DP, whe...

Research paper thumbnail of Occurrence of sickness absence and disability pension in relation to childbirth: A 16-year follow-up study of 6323 Swedish twins

Scandinavian journal of public health, Jan 12, 2015

Pregnancy, delivery, and the postpartum period may imply morbidity leading to work incapacity; ho... more Pregnancy, delivery, and the postpartum period may imply morbidity leading to work incapacity; however, this is seldom studied. This study aimed to compare twin sisters giving or not giving birth regarding occurrence of sickness absence (SA) and disability pension (DP). This population-based cohort study included all 6323 female twins born in Sweden 1959-1990, using register data for 1994-2010 about SA and DP. Average number of SA/DP days/year was calculated in relation to the year of the first delivery, or, if not giving birth, the year when the twin sister gave birth. Twin pairs discordant for delivery were used to investigate the importance of genetic and environmental factors for occurrence of SA and DP. In all, 52% had a first delivery during 1994-2010. Except for the year of delivery, the average number of SA days/year was similar when comparing women who gave birth to those who did not, while number of DP days was significantly higher in women who did not give birth. Differen...

Research paper thumbnail of Associations between Childbirth, Hospitalization and Disability Pension: A Cohort Study of Female Twins

PLoS ONE, 2014

Background: As the literature on long-term effects of childbirth on risk of morbidity or permanen... more Background: As the literature on long-term effects of childbirth on risk of morbidity or permanent work incapacity (DP) is limited, we aimed to study associations of childbirth with hospitalization and DP, adjusting for familial factors. Methods: This cohort study included female twins, i.e. women with twin sister, born 1959-1990 in Sweden (n = 5 118). At least one in the twin pair had their first childbirth 1994-2009. Women were followed regarding all-cause and cause-specific (mental or musculoskeletal diagnoses) DP during year 2-5 after first delivery or equivalent. Associations between childbirth, hospitalization and DP were calculated as hazard ratios (HR) with 95% confidence intervals (CI). Results: Women who did not give birth had markedly higher number of DP days/year compared to those giving birth. Hospitalization after first childbirth was associated with a higher HR of DP. Those hospitalized at least once after their first childbirth had a threefold DP risk (HR: 3.2; 95% CI 1.1-9.6), DP due to mental diagnoses (HR: 3.2; 1.2-8.8), and of DP due to musculoskeletal diagnoses (HR: 6.1; 1.6-22.9). Lower HRs in the discordant twin pair analyses indicated that familial factors may influence the studied associations. Conclusions: Women who did not give birth had a much higher risk for DP than those who did. Among those who gave birth, the risk for DP was markedly higher among those with a previous hospitalization, and especially in women with repeated hospitalizations. The results indicate a health selection into giving birth as well as the importance of morbidity for DP.

Research paper thumbnail of Incidence of disability pension and associations with socio-demographic factors in a Swedish twin cohort

Social Psychiatry and Psychiatric Epidemiology, 2012

Research paper thumbnail of Sleep Patterns as Predictors for Disability Pension Due to Low Back Diagnoses: A 23-Year Longitudinal Study of Finnish Twins

SLEEP, 2013

Impaired sleep patterns are known to be associated with many chronic conditions and ultimately th... more Impaired sleep patterns are known to be associated with many chronic conditions and ultimately they may lead to permanent work incapacity. Less is known about the associations between sleep patterns and cause-specific disability pensions, such as low back diagnoses, or whether familial factors (genetics and family environment) can affect the associations. The objective of this study was to investigate sleep patterns as predictors of disability pension due to low back diagnoses with a 23-year follow-up. Design and Setting: A prospective cohort study with comprehensive mailed questionnaires about sleep patterns, e.g., quality and length of sleep in 1975 and 1981. Follow-up from the national disability pension register data until 2004. Interventions: Not applicable. Participants: There were 18,979 individuals (7,722 complete twin pairs) born before 1958. Measurements and Results: Cox proportional hazards regression was used to calculate hazard ratios (HR) with 95% confidence intervals (95% CI). Disability pension due to low back diagnoses had been granted to 467 individuals during the follow-up. Sleeping moderately well (HR 1.25; 95% CI 1.02, 1.53), or fairly poorly/poorly (HR 2.05; 95% CI 1.53, 2.73) at baseline predicted a significantly higher risk for disability pension. Stable patterns of sleeping either fairly well (HR 1.29; 95% CI 1.01, 1.64), or stably fairly poorly/poorly (HR 2.29; 95% CI 1.49, 3.52) between 1975 and 1981 were associated with a higher risk as compared to a stable pattern of sleeping well. Furthermore, a decrease in quality of sleep from 1975 to 1981 was associated (HR 1.34; 95% CI 1.03, 1.76) with an increased risk of disability pension. Conclusions: Sleep quality and changes in sleep quality appear to be early predictors for disability pension due to low back diagnoses independently from other confounding factors.

Research paper thumbnail of Disability pension due to musculoskeletal diagnoses: importance of work-related factors in a prospective cohort study of Finnish twins

Scandinavian Journal of Work, Environment & Health, 2013

Several work-related risk factors, such as physical workload and stress, are independent, direct ... more Several work-related risk factors, such as physical workload and stress, are independent, direct risk factors for disability pension due to musculoskeletal diagnosis, not affected by familial factors. Identification of these risk factors during a person's lifespan would be beneficial for occupational health care and individuals to reduce permanent work incapacity due to musculoskeletal diagnosis.

Research paper thumbnail of Psychosocial working conditions, occupational groups, and risk of disability pension due to mental diagnoses: a cohort study of 43 000 Swedish twins

Scandinavian Journal of Work, Environment & Health, 2012

Psychosocial working conditions, occupational groups, and risk of disability pension due to menta... more Psychosocial working conditions, occupational groups, and risk of disability pension due to mental diagnoses: a cohort study of 43 000 Swedish twins by Samuelsson Å, Ropponen A, Alexanderson K, Svedberg P Use of twin data made it possible to account for familial confounding to the associations between psychosocial working conditions and disability pension due to mental diagnoses. After accounting for familial confounding, the associations between job demands, job control, and disability pension due to mental diagnoses remained, suggesting that these factors are independent predictors of disability pension with mental diagnoses.

Research paper thumbnail of Physical work load and psychological stress of daily activities as predictors of disability pension due to musculoskeletal disorders

Scandinavian Journal of Public Health, 2014

Aims: Physical work loading and psychological stress commonly co-occur in working life, hence pot... more Aims: Physical work loading and psychological stress commonly co-occur in working life, hence potentially having an interrelationship that may affect work incapacity. This prospective cohort study aimed to investigate the effect of stability and change in physical work loading and stress on the risk of disability pension (DP) due to musculoskeletal diagnoses (MSD), while accounting for familial confounding in these associations. Methods: Data on 12,455 twins born before 1958 were surveyed of their physical work loading and psychological stress of daily activities in 1975 and 1981. The follow-up data was collected from pension registers until 2004. Cox proportional hazards regression models were used. Results: During the follow up, 893 participants were granted DP due to MSD. Stable high (hazard ratio, HR, 2.21), but also increased physical work loading (HR 2.05) and high psychological stress (HR 2.22) were associated with increased risk for DP, and had significant interaction ( p=0....

Research paper thumbnail of Health-related risk factors for disability pensions due to musculoskeletal diagnoses: A 30-year Finnish twin cohort study

Scandinavian Journal of Public Health, 2011

Aims: There is a need to better understand work incapacity due to musculoskeletal disorders (MSD)... more Aims: There is a need to better understand work incapacity due to musculoskeletal disorders (MSD) and the factors that contribute to being granted disability pension (DP) with such disorders. A twin cohort study would serve a powerful tool responding to this knowledge gap by providing information on factors affecting DP when controlling for family background. The purpose was to investigate the incidence of and risk factors for DP due to any MSD ( n = 1,819) and specifically due to osteoarthritis (OA, n = 677) in a twin cohort of 24,043 people over a 30-year follow-up. Methods: Data on twin pairs from a mailed questionnaire during the baseline year of 1975 were followed up with register data regarding DP, emigration, old-age pension, and death. For statistical analysis, univariate and multivariate Cox proportional hazard ratios were estimated. Results: Baseline musculoskeletal pain, frequency of use of analgesics, body mass index, and chronic diseases, as well as education and social...

Research paper thumbnail of Persistent smoking as a predictor of disability pension due to musculoskeletal diagnoses: A 23year prospective study of Finnish twins

Preventive Medicine, 2013

To investigate whether stability or changes in smoking predict disability pension (DP) due to low... more To investigate whether stability or changes in smoking predict disability pension (DP) due to low back diagnoses (LBD) and musculoskeletal diagnoses (MSD) after taking familial confounding into account using a co-twin design. Longitudinal smoking patterns and multiple covariates in a population-based cohort of 17,451 Finnish twins (6959 complete pairs) born before 1958 were surveyed through questionnaires in 1975 and 1981. The outcome data were collected from the national pension registers until the end of 2004. Cox proportional hazards regression models were used for statistical analyses. Disability pension due to low back diagnoses was granted to 408 individuals and disability pension due to musculoskeletal diagnoses to 1177 individuals during the follow-up of 23 years. Being a persistent smoker (current smoker both 1975 and 1981) predicted a significantly increased risk for disability pension (hazard ratio 1.69, 95% confidence interval 1.46, 1.97) compared to those individuals who had never smoked. The association remained when several confounding factors, including familial factors, were taken into account. Persistent smoking predicts early disability pension due to musculoskeletal diagnoses and low back diagnoses independently from numerous confounding factors, including familial effects shared by the co-twins.

Research paper thumbnail of A prospective twin cohort study of disability pensions due to musculoskeletal diagnoses in relation to stability and change in pain

PAIN, 2013

Pain is known to play an important role in the pathway to becoming work disabled, in particular f... more Pain is known to play an important role in the pathway to becoming work disabled, in particular for award of disability pensions (DP) due to musculoskeletal diagnoses (MSD). This prospective cohort study investigated MSD-related pain stability and/or changes as predictors for DP during a 23-year follow-up. Additionally confounding factors were examined to elucidate whether familial effects (including genetics and family background) or socioeconomic status, other pain, or use of medication would affect the associations between pain and DP. Data were available on 11,224 twins (4399 complete pairs) born before 1958 surveyed through questionnaires about background factors and musculoskeletal (low back, neck, and shoulder) pain impairing work ability in 1975 and 1981. The follow-up data were collected from pension registers until 2004. Cox proportional hazards regression models were used. During the 23-year follow-up, 508 DPs due to MSD, 166 DPs due to osteoarthritis (OA), and 162 DPs due to low back diagnoses (LBD) were granted. Musculoskeletal pain impairing work ability both measured at 1 time point and 6 years apart, and either 1 pain location or multiple locations, predicted increased risk for DP due to MSD, OA, and LBD. The associations were independent of familial confounding factors and of several influential background factors, including headache; migraine; use of analgesics, hypnotics, or tranquillizers; life satisfaction; and education and marital status. This study concluded that musculoskeletal pain impairing work ability is an early and direct predictor for DP due to MSD, OA, and LBD.