Gavin Pereira | Yale University (original) (raw)

Papers by Gavin Pereira

Research paper thumbnail of Re-evaluation of link between interpregnancy interval and adverse birth outcomes: retrospective cohort study matching two intervals per mother

BMJ (Clinical research ed.), 2014

Objective To re-evaluate the causal effect of interpregnancy interval on adverse birth outcomes, ... more Objective To re-evaluate the causal effect of interpregnancy interval on adverse birth outcomes, on the basis that previous studies relying on between mother comparisons may have inadequately adjusted for confounding by maternal risk factors.

Research paper thumbnail of Sources of Fine Particulate Matter and Risk of Preterm Birth in Connecticut, 2000-2006: A Longitudinal Study

Environmental health perspectives, 2014

Background: Previous studies have examined fine particulate matter (PM 2.5 ) and preterm birth bu... more Background: Previous studies have examined fine particulate matter (PM 2.5 ) and preterm birth but there is a dearth of longitudinal studies on this topic and a paucity of studies that have investigated specific sources of this exposure.

Research paper thumbnail of The association between neighborhood greenness and weight status: an observational study in Perth Western Australia

Environmental health : a global access science source, 2013

Background: Few studies have examined the relationship between weight status and objectively meas... more Background: Few studies have examined the relationship between weight status and objectively measured neighborhood greenness and no study has examined this relationship across the different stages of adulthood. This research was an investigation of weight status and neighborhood greenness using objectively measured satellite remote sensing for a large population representative sample.

Research paper thumbnail of The association between neighborhood greenness and cardiovascular disease: an observational study

BMC public health, 2012

Background: Previous studies have demonstrated links between cardiovascular disease and physical ... more Background: Previous studies have demonstrated links between cardiovascular disease and physical inactivity and poor air quality, which are both associated with neighborhood greenness. However, no studies have directly investigated neighborhood greenness in relation to coronary heart disease risk. We investigated the effect of neighborhood greenness on both self-reported and hospital admissions of coronary heart disease or stroke, accounting for ambient air quality, socio-demographic, behavioral and biological factors. Method: Cross-sectional study of 11,404 adults obtained from a population representative sample for the period 2003-2009 in Perth, Western Australia. Neighborhood greenness was ascertained for a 1600 m service area surrounding the residential address using the mean and standard deviation of the Normalized Difference Vegetation Index (NDVI) obtained from remote sensing. Logistic regression was used to assess associations with medically diagnosed and hospitalization for coronary heart disease or stroke. Results: The odds of hospitalization for heart disease or stroke was 37% (95% CI: 8%, 57%) lower among adults in neighborhoods with highly variable greenness (highest tertile) compared to those in predominantly green, or predominantly non-green neighborhoods (lowest tertile). This effect was independent of the absolute levels of neighborhood greenness. There was weaker evidence for associations with the mean level of neighborhood greenness. Conclusion: Variability in neighborhood greenness is a single metric that encapsulates two potential promoters of physical activity -an aesthetically pleasing natural environment and access to urban destinations. Variability in greenness within a neighborhood was negatively associated with coronary heart disease and stroke.

Research paper thumbnail of A case-crossover analysis of traffic-related air pollution and emergency department presentations for asthma in Perth, Western Australia

The Medical journal of Australia, 2010

Research paper thumbnail of Traffic emissions are associated with reduced fetal growth in areas of Perth, Western Australia: an application of the AusRoads dispersion model

Australian and New Zealand journal of public health, 2011

Background: This study, in a region with relatively low industrial activity, used a highly specif... more Background: This study, in a region with relatively low industrial activity, used a highly specific marker for traffic emissions, accounted for the inherent fetal growth potential, and used complete record linkage of births, midwife notifications, deaths, hospital morbidity and birth defect records.Methods: Clinical records were obtained for pregnancies between 2000 and 2006 in three areas of Perth, Western Australia (n=3,501). We used carbon monoxide as a marker for locally derived traffic emissions, and assessed exposure using the AusRoads dispersion model. Fetal growth was characterised by proportion of optimal birth weight and investigated using multivariate mixed-effects regression.Results: Exposure in the third trimester was associated with a -0.49% (sd=0.23%) change in proportion of optimal birth weight per 10 μg/m3 increase in locally derived traffic emissions. However, this result was confined to one of the three study areas due to elevated exposure misclassification among women in the other two areas. Among this group, a neonate who would have otherwise attained an optimal birth weight of 3.5 kg would be expected to be born 58 g lighter for an interquartile increase in third trimester exposure, which was approximately half of the effect observed for maternal smoking during pregnancy.Conclusion: We observed an association between maternal exposure to traffic emissions and reduced fetal growth. This effect was supported by sensitivity analyses but only observed in one of the three study areas. Further studies are required to corroborate our results.

Research paper thumbnail of The efficacy of Botulinum Toxin A for spasticity and pain in adults: a systematic review and meta-analysis using the Grades of Recommendation, Assessment, Development and Evaluation approach

Clinical rehabilitation, 2013

Objectives: A systematic review and meta-analysis using the Grades of Recommendation, Assessment,... more Objectives: A systematic review and meta-analysis using the Grades of Recommendation, Assessment, Development and Evaluation (GRADE) approach to evaluate Botulinum Toxin Type A efficacy on spasticity and pain in the upper/lower limb in adults. Data Sources: Pubmed, Cinahl, Amed, Embase and Cochrane Databases. English language. 1989 to April 2013. Review methods: All randomized controlled trials on adults with spasticity of any origin in the upper or lower limb, treated with a single dose of Botulinum Toxin A, with outcome measures for pain or spasticity. Quality was assessed by GRADE, which uses a transparent, structured process for developing and presenting summaries of evidence, including its quality, for systematic reviews. Results:A total of 37 studies were reviewed. A meta-analysis was carried out on 10 for pain and 21 for spasticity. Evidence quality was low/very low for pain. No significant effect was found in the upper limb (standardised mean difference (SMD) = 0.44, confidence interval (CI) -0.02 to 0.90, Z = 1.88, P=0.06), and no effect was found in the lower limb (risk ratio (RR) = 1.01 CI 0.19 to 5.36, Z = 0.02, P=0.99). Evidence quality for spasticity was moderate. Significant effects were found for Botulinum Toxin in the upper limb (weighted mean difference (WMD) = 0.88, CI 0.63 to 1.14, Z = 6.86, P<0.00001), and the lower limb (RR=2.42, CI 1.60 to 3.65, Z=4.18, P<0.0001). Conclusion:The use of Botulinum Toxin A is supported for upper and lower limb spasticity. Further evidence is needed for spasticity-related pain. Evidence quality is reduced by inadequate study design.

Research paper thumbnail of Cancer survival and excess mortality estimates among adolescents and young adults in Western Australia, 1982-2004: a population-based study

PloS one, 2013

Background: Data are limited on cancer outcomes in adolescents and young adults.

Research paper thumbnail of Neighborhood walkability and cardiometabolic risk factors in Australian adults: an observational study

BMC public health, 2013

Background: Studies repeatedly highlight associations between the built environment and physical ... more Background: Studies repeatedly highlight associations between the built environment and physical activity, particularly walking. Fewer studies have examined associations with cardiometabolic risk factors, with associations with obesity inconsistent and scarce evidence examining associations with other cardiometabolic risk factors. We aim to investigate the association between neighborhood walkability and the prevalence of obesity, hypertension, hypercholesterolaemia, and type-2 diabetes mellitus.

Research paper thumbnail of Access to commercial destinations within the neighbourhood and walking among Australian older adults

The international journal of behavioral nutrition and physical activity, 2012

Background: Physical activity, particularly walking, is greatly beneficial to health; yet a sizea... more Background: Physical activity, particularly walking, is greatly beneficial to health; yet a sizeable proportion of older adults are insufficiently active. The importance of built environment attributes for walking is known, but few studies of older adults have examined neighbourhood destinations and none have investigated access to specific, objectively-measured commercial destinations and walking. Methods: We undertook a secondary analysis of data from the Western Australian state government's health surveillance survey for those aged 65-84 years and living in the Perth metropolitan region from 2003-2009 (n = 2,918). Individual-level road network service areas were generated at 400 m and 800 m distances, and the presence or absence of six commercial destination types within the neighbourhood service areas identified (food retail, general retail, medical care services, financial services, general services, and social infrastructure). Adjusted logistic regression models examined access to and mix of commercial destination types within neighbourhoods for associations with self-reported walking behaviour. Results: On average, the sample was aged 72.9 years (SD = 5.4), and was predominantly female (55.9%) and married (62.0%). Overall, 66.2% reported some weekly walking and 30.8% reported sufficient walking (≥150 min/week). Older adults with access to general services within 400 m (OR = 1.33, 95% CI = 1.07-1.66) and 800 m (OR = 1.20, 95% CI = 1.02-1.42), and social infrastructure within 800 m (OR = 1.19, 95% CI = 1.01-1.40) were more likely to engage in some weekly walking. Access to medical care services within 400 m (OR = 0.77, 95% CI = 0.63-0.93) and 800 m (OR = 0.83, 95% CI = 0.70-0.99) reduced the odds of sufficient walking. Access to food retail, general retail, financial services, and the mix of commercial destination types within the neighbourhood were all unrelated to walking. Conclusions: The types of neighbourhood commercial destinations that encourage older adults to walk appear to differ slightly from those reported for adult samples. Destinations that facilitate more social interaction, for example eating at a restaurant or church involvement, or provide opportunities for some incidental social contact, for example visiting the pharmacy or hairdresser, were the strongest predictors for walking among seniors in this study. This underscores the importance of planning neighbourhoods with proximate access to social infrastructure, and highlights the need to create residential environments that support activity across the life course.

Research paper thumbnail of Maternal and neonatal outcomes in pregnancies following colorectal cancer

Surgical endoscopy, 2013

Background The risks of adverse obstetric outcomes among young women survivors of colorectal canc... more Background The risks of adverse obstetric outcomes among young women survivors of colorectal cancer (CRC) are uncertain. Methods This Western Australian, whole-jurisdictional linked-data, retrospective cohort study compared maternal and neonatal outcomes of first postcancer pregnancies among women CRC survivors against randomly selected pregnancies of women with no cancer history. Logistic regression models were used to investigate a range of adverse outcomes independently associated with CRC and its surgical and adjunctive treatments. Results Among 627,762 deliveries during the study period (1983–2007), 232 were first pregnancies following CRC. Whether following laparoscopic or open cancer surgery, these pregnancies were independently associated with a significantly increased risk of antepartum hemorrhage [odds ratios (ORs): 1.25; 2.13 for the respective procedures], postpartum hemorrhage (ORs: 1.61; 3.31), Cesarean delivery (ORs: 2.42; 4.24), infant low Apgar score (ORs: 1.32; 2.64), need for neonatal resuscitation (ORs: 1.49; 3.20), and special care admission (ORs: 1.42; 2.87). A history of open (but not laparoscopic) cancer surgery was associated with increased risk of gastrointestinal obstruction during pregnancy (OR 1.17) and prolonged postpartum hospitalization (OR 3.11). Neither was significantly associated with perinatal death. Among women with previous CRC, rectal (versus colonic) malignancy was independently associated with a significantly higher risk of overall maternal and neonatal adverse outcomes (ORs: 3.73 and 2.73, respectively), as was radiotherapy (ORs: 4.24 and 2.81, respectively). Chemotherapy was independently associated with a marginally but significantly higher risk of overall maternal but not neonatal outcomes (ORs: 1.11; 0.98). Open versus laparoscopic cancer surgery was associated with a significantly higher risk of antepartum and postpartum hemorrhage, low Apgar score, need for neonatal resuscitation, and neonatal special care admission. Conclusions Previous CRCs, particularly rectal and radiation-treated tumors, appear to confer an increased likelihood of adverse outcomes in subsequent pregnancies. Laparoscopic technique for CRC surgery may reduce adverse gestational outcomes.

Research paper thumbnail of Socioeconomic area disparities in tobacco retail outlet density: a Western Australian analysis

The Medical journal of Australia, 2013

Research paper thumbnail of Access to alcohol outlets, alcohol consumption and mental health

PloS one, 2013

The objective of this study was to investigate residential exposure to alcohol outlets in relatio... more The objective of this study was to investigate residential exposure to alcohol outlets in relation to alcohol consumption and mental health morbidity (anxiety, stress, and depression). This was a cross-sectional study of 6,837 adults obtained from a population representative sample for the period 2006-2009 in Perth, Western Australia. The number of alcohol outlets was ascertained for a 1600 m service area surrounding the residential address. Zero-inflated negative binomial and logistic regression were used to assess associations with total alcohol consumption, harmful alcohol consumption (7-10 drinks containing 10 g of alcohol for men, 5-6 drinks for women) and medically diagnosed and hospital contacts (for anxiety, stress, and depression), respectively. The rate ratio for the number of days of harmful consumption of alcohol per month and the number of standard drinks of alcohol consumed per drinking day was 1.06 (95% CI: 1.02, 1.11) and 1.01 (95% CI: 1.00, 1.03) for each additional liquor store within a 1600 m service area, respectively. The odds ratio of hospital contact for anxiety, stress, or depression was 1.56 (95% CI: 0.98, 2.49) for those with a liquor store within the service area compared to those without. We observed strong evidence for a small association between residential exposure to liquor stores and harmful consumption of alcohol, and some support for a moderate-sized effect on hospital contacts for anxiety, stress, and depression.

Research paper thumbnail of Role of public and private funding in the rising caesarean section rate: a cohort study

BMJ open, 2013

Objective: The caesarean section rates have been rising in the developed world for over two decad... more Objective: The caesarean section rates have been rising in the developed world for over two decades. This study assessed the involvement of the public and private health sectors in this increase. Design: Population-based, retrospective cohort study. Setting: Public and private hospitals in Western Australia. Participants: Included in this study were 155 646 births to nulliparous women during 1996-2008.

Research paper thumbnail of Locally derived traffic-related air pollution and fetal growth restriction: a retrospective cohort study

Occupational and environmental medicine, 2012

Research paper thumbnail of Association between pre-eclampsia and locally derived traffic-related air pollution: a retrospective cohort study

Journal of epidemiology and community health, 2013

Background Pre-eclampsia is a common complication of pregnancy and is a major cause of fetalemate... more Background Pre-eclampsia is a common complication of pregnancy and is a major cause of fetalematernal mortality and morbidity. Despite a number of plausible mechanisms by which air pollutants might contribute to this process, few studies have investigated the association between pre-eclampsia and traffic emissions, a major contributor to air pollution in urban areas.

Research paper thumbnail of Spatial and temporal variation in type 1 diabetes incidence in Western Australia from 1991 to 2010: Increased risk at higher latitudes and over time

Research paper thumbnail of Use of a total traffic count metric to investigate the impact of roadways on asthma severity: a case-control study

Environmental Health, 2011

Background This study had two principal objectives: (i) to investigate the relationship between a... more Background This study had two principal objectives: (i) to investigate the relationship between asthma severity and proximity to major roadways in Perth, Western Australia; (ii) to demonstrate a more accurate method of exposure assessment for traffic pollutants using an innovative GIS-based measure that fully integrates all traffic densities around subject residences. Methods We conducted a spatial case-control study, in which 'cases' were defined as individuals aged under 19 years of age with more severe asthma (defined here as two or more emergency department contacts with asthma in a defined 5-year period) versus age- and gender-matched 'controls' with less severe asthma (defined here as one emergency department contact for asthma). Traffic exposures were measured using a GIS-based approach to determine the lengths of the roads falling within a buffer area, and then multiplying them by their respective traffic counts. Results We examined the spatial relationship between emergency department contacts for asthma at three different buffer sizes: 50 metres, 100 metres and 150 metres. No effect was noted for the 50 metre buffer (OR = 1.07; 95% CI: 0.91-1.26), but elevated odds ratios were observed with for crude (unadjusted) estimates OR = 1.21 (95% CI: 1.00-1.46) for 100 metre buffers and OR = 1.25 (95% CI: 1.02-1.54) for 150 metre buffers. For adjusted risk estimates, only the 150 metre buffer yielded a statistically significant finding (OR = 1.24; 95% CI:1.00-1.52). Conclusions Our study revealed a significant 24% increase in the risk of experiencing multiple emergency department contacts for asthma for every log-unit of traffic exposure. This study provides support for the hypothesis that traffic related air pollution increases the frequency of health service contacts for asthma. This study used advanced GIS techniques to establish traffic-weighted buffer zones around the geocoded residential location of subjects to provide an accurate assessment of exposure to traffic emissions, thereby providing a quantification of the ranges over which pollutants may exert a health effect.

Research paper thumbnail of Vector fields of risk: A new approach to the geographical representation of childhood asthma

Research paper thumbnail of Seasonal variation in fetal growth: accounting for sociodemographic, biological, and environmental exposures

American Journal of Obstetrics and Gynecology

OBJECTIVE: We sought to investigate seasonal variation in fetal growth, accounting for important ... more OBJECTIVE: We sought to investigate seasonal variation in fetal growth, accounting for important sociodemographic, biological, and environmental exposures.

Research paper thumbnail of Re-evaluation of link between interpregnancy interval and adverse birth outcomes: retrospective cohort study matching two intervals per mother

BMJ (Clinical research ed.), 2014

Objective To re-evaluate the causal effect of interpregnancy interval on adverse birth outcomes, ... more Objective To re-evaluate the causal effect of interpregnancy interval on adverse birth outcomes, on the basis that previous studies relying on between mother comparisons may have inadequately adjusted for confounding by maternal risk factors.

Research paper thumbnail of Sources of Fine Particulate Matter and Risk of Preterm Birth in Connecticut, 2000-2006: A Longitudinal Study

Environmental health perspectives, 2014

Background: Previous studies have examined fine particulate matter (PM 2.5 ) and preterm birth bu... more Background: Previous studies have examined fine particulate matter (PM 2.5 ) and preterm birth but there is a dearth of longitudinal studies on this topic and a paucity of studies that have investigated specific sources of this exposure.

Research paper thumbnail of The association between neighborhood greenness and weight status: an observational study in Perth Western Australia

Environmental health : a global access science source, 2013

Background: Few studies have examined the relationship between weight status and objectively meas... more Background: Few studies have examined the relationship between weight status and objectively measured neighborhood greenness and no study has examined this relationship across the different stages of adulthood. This research was an investigation of weight status and neighborhood greenness using objectively measured satellite remote sensing for a large population representative sample.

Research paper thumbnail of The association between neighborhood greenness and cardiovascular disease: an observational study

BMC public health, 2012

Background: Previous studies have demonstrated links between cardiovascular disease and physical ... more Background: Previous studies have demonstrated links between cardiovascular disease and physical inactivity and poor air quality, which are both associated with neighborhood greenness. However, no studies have directly investigated neighborhood greenness in relation to coronary heart disease risk. We investigated the effect of neighborhood greenness on both self-reported and hospital admissions of coronary heart disease or stroke, accounting for ambient air quality, socio-demographic, behavioral and biological factors. Method: Cross-sectional study of 11,404 adults obtained from a population representative sample for the period 2003-2009 in Perth, Western Australia. Neighborhood greenness was ascertained for a 1600 m service area surrounding the residential address using the mean and standard deviation of the Normalized Difference Vegetation Index (NDVI) obtained from remote sensing. Logistic regression was used to assess associations with medically diagnosed and hospitalization for coronary heart disease or stroke. Results: The odds of hospitalization for heart disease or stroke was 37% (95% CI: 8%, 57%) lower among adults in neighborhoods with highly variable greenness (highest tertile) compared to those in predominantly green, or predominantly non-green neighborhoods (lowest tertile). This effect was independent of the absolute levels of neighborhood greenness. There was weaker evidence for associations with the mean level of neighborhood greenness. Conclusion: Variability in neighborhood greenness is a single metric that encapsulates two potential promoters of physical activity -an aesthetically pleasing natural environment and access to urban destinations. Variability in greenness within a neighborhood was negatively associated with coronary heart disease and stroke.

Research paper thumbnail of A case-crossover analysis of traffic-related air pollution and emergency department presentations for asthma in Perth, Western Australia

The Medical journal of Australia, 2010

Research paper thumbnail of Traffic emissions are associated with reduced fetal growth in areas of Perth, Western Australia: an application of the AusRoads dispersion model

Australian and New Zealand journal of public health, 2011

Background: This study, in a region with relatively low industrial activity, used a highly specif... more Background: This study, in a region with relatively low industrial activity, used a highly specific marker for traffic emissions, accounted for the inherent fetal growth potential, and used complete record linkage of births, midwife notifications, deaths, hospital morbidity and birth defect records.Methods: Clinical records were obtained for pregnancies between 2000 and 2006 in three areas of Perth, Western Australia (n=3,501). We used carbon monoxide as a marker for locally derived traffic emissions, and assessed exposure using the AusRoads dispersion model. Fetal growth was characterised by proportion of optimal birth weight and investigated using multivariate mixed-effects regression.Results: Exposure in the third trimester was associated with a -0.49% (sd=0.23%) change in proportion of optimal birth weight per 10 μg/m3 increase in locally derived traffic emissions. However, this result was confined to one of the three study areas due to elevated exposure misclassification among women in the other two areas. Among this group, a neonate who would have otherwise attained an optimal birth weight of 3.5 kg would be expected to be born 58 g lighter for an interquartile increase in third trimester exposure, which was approximately half of the effect observed for maternal smoking during pregnancy.Conclusion: We observed an association between maternal exposure to traffic emissions and reduced fetal growth. This effect was supported by sensitivity analyses but only observed in one of the three study areas. Further studies are required to corroborate our results.

Research paper thumbnail of The efficacy of Botulinum Toxin A for spasticity and pain in adults: a systematic review and meta-analysis using the Grades of Recommendation, Assessment, Development and Evaluation approach

Clinical rehabilitation, 2013

Objectives: A systematic review and meta-analysis using the Grades of Recommendation, Assessment,... more Objectives: A systematic review and meta-analysis using the Grades of Recommendation, Assessment, Development and Evaluation (GRADE) approach to evaluate Botulinum Toxin Type A efficacy on spasticity and pain in the upper/lower limb in adults. Data Sources: Pubmed, Cinahl, Amed, Embase and Cochrane Databases. English language. 1989 to April 2013. Review methods: All randomized controlled trials on adults with spasticity of any origin in the upper or lower limb, treated with a single dose of Botulinum Toxin A, with outcome measures for pain or spasticity. Quality was assessed by GRADE, which uses a transparent, structured process for developing and presenting summaries of evidence, including its quality, for systematic reviews. Results:A total of 37 studies were reviewed. A meta-analysis was carried out on 10 for pain and 21 for spasticity. Evidence quality was low/very low for pain. No significant effect was found in the upper limb (standardised mean difference (SMD) = 0.44, confidence interval (CI) -0.02 to 0.90, Z = 1.88, P=0.06), and no effect was found in the lower limb (risk ratio (RR) = 1.01 CI 0.19 to 5.36, Z = 0.02, P=0.99). Evidence quality for spasticity was moderate. Significant effects were found for Botulinum Toxin in the upper limb (weighted mean difference (WMD) = 0.88, CI 0.63 to 1.14, Z = 6.86, P<0.00001), and the lower limb (RR=2.42, CI 1.60 to 3.65, Z=4.18, P<0.0001). Conclusion:The use of Botulinum Toxin A is supported for upper and lower limb spasticity. Further evidence is needed for spasticity-related pain. Evidence quality is reduced by inadequate study design.

Research paper thumbnail of Cancer survival and excess mortality estimates among adolescents and young adults in Western Australia, 1982-2004: a population-based study

PloS one, 2013

Background: Data are limited on cancer outcomes in adolescents and young adults.

Research paper thumbnail of Neighborhood walkability and cardiometabolic risk factors in Australian adults: an observational study

BMC public health, 2013

Background: Studies repeatedly highlight associations between the built environment and physical ... more Background: Studies repeatedly highlight associations between the built environment and physical activity, particularly walking. Fewer studies have examined associations with cardiometabolic risk factors, with associations with obesity inconsistent and scarce evidence examining associations with other cardiometabolic risk factors. We aim to investigate the association between neighborhood walkability and the prevalence of obesity, hypertension, hypercholesterolaemia, and type-2 diabetes mellitus.

Research paper thumbnail of Access to commercial destinations within the neighbourhood and walking among Australian older adults

The international journal of behavioral nutrition and physical activity, 2012

Background: Physical activity, particularly walking, is greatly beneficial to health; yet a sizea... more Background: Physical activity, particularly walking, is greatly beneficial to health; yet a sizeable proportion of older adults are insufficiently active. The importance of built environment attributes for walking is known, but few studies of older adults have examined neighbourhood destinations and none have investigated access to specific, objectively-measured commercial destinations and walking. Methods: We undertook a secondary analysis of data from the Western Australian state government's health surveillance survey for those aged 65-84 years and living in the Perth metropolitan region from 2003-2009 (n = 2,918). Individual-level road network service areas were generated at 400 m and 800 m distances, and the presence or absence of six commercial destination types within the neighbourhood service areas identified (food retail, general retail, medical care services, financial services, general services, and social infrastructure). Adjusted logistic regression models examined access to and mix of commercial destination types within neighbourhoods for associations with self-reported walking behaviour. Results: On average, the sample was aged 72.9 years (SD = 5.4), and was predominantly female (55.9%) and married (62.0%). Overall, 66.2% reported some weekly walking and 30.8% reported sufficient walking (≥150 min/week). Older adults with access to general services within 400 m (OR = 1.33, 95% CI = 1.07-1.66) and 800 m (OR = 1.20, 95% CI = 1.02-1.42), and social infrastructure within 800 m (OR = 1.19, 95% CI = 1.01-1.40) were more likely to engage in some weekly walking. Access to medical care services within 400 m (OR = 0.77, 95% CI = 0.63-0.93) and 800 m (OR = 0.83, 95% CI = 0.70-0.99) reduced the odds of sufficient walking. Access to food retail, general retail, financial services, and the mix of commercial destination types within the neighbourhood were all unrelated to walking. Conclusions: The types of neighbourhood commercial destinations that encourage older adults to walk appear to differ slightly from those reported for adult samples. Destinations that facilitate more social interaction, for example eating at a restaurant or church involvement, or provide opportunities for some incidental social contact, for example visiting the pharmacy or hairdresser, were the strongest predictors for walking among seniors in this study. This underscores the importance of planning neighbourhoods with proximate access to social infrastructure, and highlights the need to create residential environments that support activity across the life course.

Research paper thumbnail of Maternal and neonatal outcomes in pregnancies following colorectal cancer

Surgical endoscopy, 2013

Background The risks of adverse obstetric outcomes among young women survivors of colorectal canc... more Background The risks of adverse obstetric outcomes among young women survivors of colorectal cancer (CRC) are uncertain. Methods This Western Australian, whole-jurisdictional linked-data, retrospective cohort study compared maternal and neonatal outcomes of first postcancer pregnancies among women CRC survivors against randomly selected pregnancies of women with no cancer history. Logistic regression models were used to investigate a range of adverse outcomes independently associated with CRC and its surgical and adjunctive treatments. Results Among 627,762 deliveries during the study period (1983–2007), 232 were first pregnancies following CRC. Whether following laparoscopic or open cancer surgery, these pregnancies were independently associated with a significantly increased risk of antepartum hemorrhage [odds ratios (ORs): 1.25; 2.13 for the respective procedures], postpartum hemorrhage (ORs: 1.61; 3.31), Cesarean delivery (ORs: 2.42; 4.24), infant low Apgar score (ORs: 1.32; 2.64), need for neonatal resuscitation (ORs: 1.49; 3.20), and special care admission (ORs: 1.42; 2.87). A history of open (but not laparoscopic) cancer surgery was associated with increased risk of gastrointestinal obstruction during pregnancy (OR 1.17) and prolonged postpartum hospitalization (OR 3.11). Neither was significantly associated with perinatal death. Among women with previous CRC, rectal (versus colonic) malignancy was independently associated with a significantly higher risk of overall maternal and neonatal adverse outcomes (ORs: 3.73 and 2.73, respectively), as was radiotherapy (ORs: 4.24 and 2.81, respectively). Chemotherapy was independently associated with a marginally but significantly higher risk of overall maternal but not neonatal outcomes (ORs: 1.11; 0.98). Open versus laparoscopic cancer surgery was associated with a significantly higher risk of antepartum and postpartum hemorrhage, low Apgar score, need for neonatal resuscitation, and neonatal special care admission. Conclusions Previous CRCs, particularly rectal and radiation-treated tumors, appear to confer an increased likelihood of adverse outcomes in subsequent pregnancies. Laparoscopic technique for CRC surgery may reduce adverse gestational outcomes.

Research paper thumbnail of Socioeconomic area disparities in tobacco retail outlet density: a Western Australian analysis

The Medical journal of Australia, 2013

Research paper thumbnail of Access to alcohol outlets, alcohol consumption and mental health

PloS one, 2013

The objective of this study was to investigate residential exposure to alcohol outlets in relatio... more The objective of this study was to investigate residential exposure to alcohol outlets in relation to alcohol consumption and mental health morbidity (anxiety, stress, and depression). This was a cross-sectional study of 6,837 adults obtained from a population representative sample for the period 2006-2009 in Perth, Western Australia. The number of alcohol outlets was ascertained for a 1600 m service area surrounding the residential address. Zero-inflated negative binomial and logistic regression were used to assess associations with total alcohol consumption, harmful alcohol consumption (7-10 drinks containing 10 g of alcohol for men, 5-6 drinks for women) and medically diagnosed and hospital contacts (for anxiety, stress, and depression), respectively. The rate ratio for the number of days of harmful consumption of alcohol per month and the number of standard drinks of alcohol consumed per drinking day was 1.06 (95% CI: 1.02, 1.11) and 1.01 (95% CI: 1.00, 1.03) for each additional liquor store within a 1600 m service area, respectively. The odds ratio of hospital contact for anxiety, stress, or depression was 1.56 (95% CI: 0.98, 2.49) for those with a liquor store within the service area compared to those without. We observed strong evidence for a small association between residential exposure to liquor stores and harmful consumption of alcohol, and some support for a moderate-sized effect on hospital contacts for anxiety, stress, and depression.

Research paper thumbnail of Role of public and private funding in the rising caesarean section rate: a cohort study

BMJ open, 2013

Objective: The caesarean section rates have been rising in the developed world for over two decad... more Objective: The caesarean section rates have been rising in the developed world for over two decades. This study assessed the involvement of the public and private health sectors in this increase. Design: Population-based, retrospective cohort study. Setting: Public and private hospitals in Western Australia. Participants: Included in this study were 155 646 births to nulliparous women during 1996-2008.

Research paper thumbnail of Locally derived traffic-related air pollution and fetal growth restriction: a retrospective cohort study

Occupational and environmental medicine, 2012

Research paper thumbnail of Association between pre-eclampsia and locally derived traffic-related air pollution: a retrospective cohort study

Journal of epidemiology and community health, 2013

Background Pre-eclampsia is a common complication of pregnancy and is a major cause of fetalemate... more Background Pre-eclampsia is a common complication of pregnancy and is a major cause of fetalematernal mortality and morbidity. Despite a number of plausible mechanisms by which air pollutants might contribute to this process, few studies have investigated the association between pre-eclampsia and traffic emissions, a major contributor to air pollution in urban areas.

Research paper thumbnail of Spatial and temporal variation in type 1 diabetes incidence in Western Australia from 1991 to 2010: Increased risk at higher latitudes and over time

Research paper thumbnail of Use of a total traffic count metric to investigate the impact of roadways on asthma severity: a case-control study

Environmental Health, 2011

Background This study had two principal objectives: (i) to investigate the relationship between a... more Background This study had two principal objectives: (i) to investigate the relationship between asthma severity and proximity to major roadways in Perth, Western Australia; (ii) to demonstrate a more accurate method of exposure assessment for traffic pollutants using an innovative GIS-based measure that fully integrates all traffic densities around subject residences. Methods We conducted a spatial case-control study, in which 'cases' were defined as individuals aged under 19 years of age with more severe asthma (defined here as two or more emergency department contacts with asthma in a defined 5-year period) versus age- and gender-matched 'controls' with less severe asthma (defined here as one emergency department contact for asthma). Traffic exposures were measured using a GIS-based approach to determine the lengths of the roads falling within a buffer area, and then multiplying them by their respective traffic counts. Results We examined the spatial relationship between emergency department contacts for asthma at three different buffer sizes: 50 metres, 100 metres and 150 metres. No effect was noted for the 50 metre buffer (OR = 1.07; 95% CI: 0.91-1.26), but elevated odds ratios were observed with for crude (unadjusted) estimates OR = 1.21 (95% CI: 1.00-1.46) for 100 metre buffers and OR = 1.25 (95% CI: 1.02-1.54) for 150 metre buffers. For adjusted risk estimates, only the 150 metre buffer yielded a statistically significant finding (OR = 1.24; 95% CI:1.00-1.52). Conclusions Our study revealed a significant 24% increase in the risk of experiencing multiple emergency department contacts for asthma for every log-unit of traffic exposure. This study provides support for the hypothesis that traffic related air pollution increases the frequency of health service contacts for asthma. This study used advanced GIS techniques to establish traffic-weighted buffer zones around the geocoded residential location of subjects to provide an accurate assessment of exposure to traffic emissions, thereby providing a quantification of the ranges over which pollutants may exert a health effect.

Research paper thumbnail of Vector fields of risk: A new approach to the geographical representation of childhood asthma

Research paper thumbnail of Seasonal variation in fetal growth: accounting for sociodemographic, biological, and environmental exposures

American Journal of Obstetrics and Gynecology

OBJECTIVE: We sought to investigate seasonal variation in fetal growth, accounting for important ... more OBJECTIVE: We sought to investigate seasonal variation in fetal growth, accounting for important sociodemographic, biological, and environmental exposures.