Are our babies becoming bigger? (original) (raw)
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Trends and social patterning of birthweight in Sheffield, 1985-94
Archives of Disease in Childhood - Fetal and Neonatal Edition, 1999
Aim-To describe the trends in birthweight and their association with socioeconomic status in a 10 year birth cohort in SheYeld. Methods-Data for all live singleton births were extracted from the SheYeld Child Development Study (SCDS) database for 1985-94. Enumeration districts (EDs), derived from postcodes, were ranked into deciles by Townsend Deprivation Index (TDI), based on the 1991 census. Birthweight by 500 g group and mean birthweights for the city and by ED decile were calculated by year. 2 analyses for linear trend were calculated. The proportion of variance in birthweight explained by ED decile and raw TDI score was estimated by year. Absolute risk diVerence of birthweight <3500 g for the most compared with the least deprived deciles and proportion of births <3500 g statistically "attributable" to social inequality were calculated. Results-The mean birthweight for all births increased by 34 g between 1985 and 1994. This diVerence is largely accounted for by a positive trend in births >3500 g and a negative trend in births of 3000-3499 g. Similar trends were noted across all ED deciles. Around 10% of the variance in birthweight was explained by area deprivation level. Absolute risk difference for births <3500 g was 12.5% for the 10 years (range 8.3-18.4). The proportion of births <3500 g statistically "attributable" to social inequality for the 10 year period was 9.6% (range 4.3-15.5). Conclusions-Despite an overall increase in mean birthweight, large social diVerences persisted during the study period. An average of 350 births a year were not in the group (>3500 g) bestowing most health advantage throughout the life course, as a result of social inequality.
Human Reproduction, 2009
Maternal education is associated with the birthweight of offspring. We sought to quantify the role of maternal body mass index (BMI) and smoking as intermediary variables between maternal education and birthweight at term. methods: We examined the association between maternal education, BMI, smoking and offspring's birthweight among women who delivered at term in the Danish National Birth Cohort (n = 75 085). results: Compared with mothers with more than 12 years of education, women with 10-12 years of education had babies that were 12 (4-19) g lighter. Mothers with 9 years of education had babies that were 51 (95% CI; 39-62) g lighter. BMI and smoking affected the association between maternal education and birthweight, albeit in different directions. If all mothers had the BMI of the highest educated mothers, the deficits would be larger: 220 (222 to 219) and 274 (280 to 268) g, respectively. If all mothers smoked like the highest educated mothers, mothers with a shorter education would have the heaviest babies: the difference would be 9 (2-16) and 23 (11-36) g, respectively. In combination, smoking and BMI all but explained the educational gradient in birthweight at term. conclusion: Maternal smoking and BMI are important intermediates of the educational gradient in birthweight at term. As the prevalence of smoking is dropping and the prevalence of obesity is increasing the educational gradient will likely reverse, but it seems unlikely that this will translate into a health advantage for the children of the least educated mothers.
Low Birth Weight Trends in OECD Countries, 2000-2015: Economic and Health System Conditionings
Background: Low birth weight rates are increasing in developed countries. However, little is known of economic or organization factors influencing this increase. This study aims to ascertain the 21st century relationships between the contextual country factors and low birth weight rates.Methods: We analyse trends of low birth weight rates in OECD countries. Data from 2000 to 2015 were obtained from the OECD data base. Their relationships with demographic and economic variables, health habits, woman-related preventive measures, health care system organization and funding, health care work force and obstetric care were analysed using random-effects linear regression.Results: Low birth weight rates are higher in Southern Europe and lower in Northern Europe. Low birth weight rates escalated about 20% in Southern Europe and to less extent in Easter Europe and Asian/Oceanian countries, while remained stable in America, Central Europe and Northern Europe. Investment in health care, private...
Epidemiology, 2002
Background. Previous studies have suggested that a population's entire birth weight distribution may be shifted towards higher or lower birth weights, and that optimal birth weight may be lower in populations with a lower average birth weight. We evaluated this hypothesis for seven western European countries. Methods. We obtained data on all singleton births (N ϭ 1,372,092) and extended perinatal deaths (stillbirths plus neonatal deaths; N ϭ 7,900) occurring in Finland, Sweden, Norway, Denmark, Scotland, the Netherlands, and Flanders (Belgium) in 1993-1995. We assessed whether countries differed in the mode of their birth weight distribution and in the birth weight associated with the lowest perinatal mortality, and then correlated the two. Results. Substantial international differences were found in the mode of the birth weight distribution, which ranged between 3384 gm in Flanders and 3628 gm in Finland. The position of the minimum of the perinatal mortality curve also differed considerably, ranging between 3755 gm in Flanders and 4305 gm in Norway. There was a strong relation between the two: for every 100 gm increase in modal birth weight, optimal birth weight was 170 gm higher (95% confidence interval ϭ 104-236 gm). Conclusions. Our results confirm those of previous studies that compared two populations. To improve the identification of small babies at high risk of perinatal death, population-specific standards for birth weight should be developed and used.
Paediatric and Perinatal Epidemiology, 2005
Low birthweight (LBW) is highly associated with death during infancy, and countries with the highest LBW rates also have the highest infant mortality rates. We compared temporal trends in LBW with both overall and birthweight-specific infant mortality in United States, Canada, Argentina, Chile, and Uruguay over two time periods, using cohort and cross-sectional analysis of national population-based vital statistics for 1985-89 and 1995-98. Infant mortality diminished substantially (RR = 0.60-0.80 for the later vs. earlier periods) and to a similar degree in all birthweight categories in all five study countries, despite an increase in LBW in the US and Uruguay, minimal changes in Canada and Argentina, and a decrease in Chile. The strength of the (positive) association between LBW and overall infant mortality diminished over the two time periods (from r s = + 0.80 to + 0.25 and RR per SD increase in LBW rate from 2.13 [2.09, 2.17] to 1.76 [1.74, 1.79]). The proportion of infant deaths occurring among LBW infants was negatively correlated with overall infant mortality in both time periods (r s = -0.30 and -0.60, RR = 0.68 [0.67, 0.68] and 0.47 [0.46, 0.47]). Developed and less developed countries in the Americas have succeeded in reducing infant mortality in all birthweight groups despite inconsistent changes in LBW rates, and none has achieved this success primarily by reducing LBW. Although our results are not necessarily generalisable to the least developed countries in South Asia and sub-Saharan Africa, it is likely that all countries can substantially reduce their infant mortality rates by improving the care of infants at normal and low birthweights.
Ethnic differences in term birthweight: the role of constitutional and environmental factors
Paediatric and Perinatal Epidemiology, 2008
It is not clear to what extent ethnic differences in the term birthweight distribution are constitutional or pathological. This study explored term birthweight heterogeneity between ethnic groups and the explanatory role of constitutional and environmental factors. As part of a prospective cohort study, the Amsterdam Born Children and their Development study, 8266 pregnant women filled out a questionnaire during early pregnancy. Ethnic groups were categorised as: native Dutch group; first and second generation Surinamese, Antillean, Turkish, Moroccan, Ghanaian and other non-Dutch groups. Only singleton livebirths with ≥37.0 weeks of gestation and with complete data were included for analysis (n = 7118). We performed linear regression analyses to estimate the association between ethnicity and, for gestational age, standardised birthweight at term, adjusted for constitutional (fetal gender, parity, maternal age, maternal height) and environmental (education, cohabitation status, maternal body mass index, smoking, alcohol consumption, depression, work stress) determinants respectively.Mean birthweight ranged from 3223 g (second generation Surinamese newborns) to 3548 g (Dutch newborns). Adjustment for constitutional factors substantially reduced the ethnic differences in birthweight, while adjustment for environmental factors provided little additional explanation. Surinamese [first generation: regression coefficient (b) = −98.3 g, P < 0.001; second generation: b = −159.3 g, P < 0.001], first generation Antillean (b = −102.0 g, P = 0.037), and Ghanaian newborns (b = −120.7 g, P = 0.001) remained significantly smaller than Dutch newborns after adjustment for all determinants. Term birthweight differences between Dutch newborns and Turkish, Moroccan and other non-Dutch newborns were largely explained by constitutional rather than environmental determinants, limiting the need for prevention. Surinamese, Antillean and Ghanaian (mainly black) newborns remained unexplainably smaller after adjustment, leaving the possibility of either unknown constitutional or pathological underlying mechanisms.
BMC Pregnancy and Childbirth, 2021
Background Low birth weight rates are increasing in both developed and developing countries. Although several maternal factors have been identified as associated with low birth weight, little is known of economic or organization factors influencing this increase. This study aims to ascertain the twenty-first century relationships between the contextual country factors and low birth weight rates. Methods We analyse trends of low birth weight rates in Organisation for Economic Co-operation and Development (OECD) countries. Data from 2000 to 2015 were obtained from the OECD data base. Their relationships with demographic and economic variables, health habits, woman-related preventive measures, health care system organization and funding, health care work force and obstetric care were analysed using random-effects linear regression. Results Low birth weight rates are higher in Southern Europe (7.61%) and lower in Northern Europe (4.68%). Low birth weight rates escalated about 20% in Sou...