Birth Weight, Childhood and Young Adult Overweight, and the Risk of Coronary Heart Disease in Men.

BACKGROUND: Low birth weight is a known risk factor for adult coronary heart disease (CHD), but the additional effect of weight development during childhood and early adult life has not been studied. METHODS: We included 35 659 men born 1945 to 1961 from the population-based BMI Epidemiology Study Gothenburg, with data available on birthweight, BMI in childhood (8 years), and BMI in young adulthood (20 years). Information on CHD diagnoses was retrieved from national registers. We used Cox proportional hazards regression to estimate hazard ratios and 95% CIs for the risk of early and late CHD (before and after 58.4 years of age, respectively). RESULTS: During follow-up, a total of 3380 cases of CHD (fatal and nonfatal) were registered. Birth weight was inversely associated with the risk of both early (hazard ratio, 0.88 per SD increase [95% CI, 0.84-0.92]) and late (hazard ratio, 0.94 per SD increase [95% CI, 0.90-0.98]) CHD, independently of BMI at 8 years and BMI change during puberty. In a model including birth weight (below or above the median) together with overweight at 8 and 20 years, only birth weight and young adult overweight, but not overweight in childhood, were significantly associated with the risk of CHD. A birth weight below the median, followed by overweight at 20 years of age was associated with a more than doubled risk of early CHD (hazard ratio, 2.29 [95% CI, 1.86-2.81]), compared with the reference (birth weight above the median and normal weight at 20 years of age). This excess risk was even more pronounced for a birthweight below 2.5 kg. CONCLUSIONS: We demonstrate that low birth weight and young adult overweight are important developmental markers of risk for adult CHD. These findings motivate a life course perspective for prevention and risk assessment of adult CHD.

Low birthweight and overweight during childhood and young adulthood and the risk of type 2 diabetes in men: a population-based cohort study.

AIMS/HYPOTHESIS: This study aimed to determine the relative contributions of low birthweight and overweight during childhood and young adulthood to the risk of type 2 diabetes in men. METHODS: We included 34,231 men born between1945 and 1961 from the population-based BMI Epidemiology Study (BEST) Gothenburg with data on birthweight and overweight status in childhood (8 years, BMI >17.9 kg/m2) and young adulthood (20 years, BMI >25 kg/m2). Participants were followed from age 30 years until 31 December 2019. Information on type 2 diabetes diagnoses was retrieved from Swedish national registers. HRs and 95% CIs for the risk of early (≤59.4 years) and late (>59.4 years) type 2 diabetes were estimated using Cox proportional hazards regression. RESULTS: During follow-up, a total of 2733 cases of type 2 diabetes were diagnosed. Birthweight below the median (<3.6 kg) and overweight at age 20 (BMI >25 kg/m2), but not overweight at age 8 (BMI >17.9 kg/m2), were associated with an increased risk of early and late type 2 diabetes. Of note, a birthweight below the median followed by overweight at age 20 years was associated with a substantially increased risk of early type 2 diabetes (HR 6.07, 95% CI 5.08, 7.27), and a low birthweight (≤2.5 kg) combined with overweight at age 20 years was associated with a massive risk of early type 2 diabetes (HR 9.94, 95% CI 6.57, 15.05). CONCLUSIONS/INTERPRETATION: Low birthweight and overweight in young adulthood are the major developmental determinants of adult type 2 diabetes risk in men. They contribute in an additive manner to the risk of type 2 diabetes. To reduce the risk of type 2 diabetes, young adult overweight should be avoided, especially in boys with a low birthweight. DATA AVAILABILITY: The SPSS analysis code, the R analysis code and a data dictionary have been made available in an online repository ( https://osf.io/bx2as/ ).

Impact of BMI and smoking in adolescence and at the start of pregnancy on birth weight.

BACKGROUND: Birth weight is an indicator of intra-uterine conditions but also a determinant for future health. The importance of preconception health for a healthy birth weight has been emphasized, but evidence is lacking on how modifiable factors in adolescence, such as body mass index (BMI) and smoking, affect future pregnancy outcome. We evaluated associations between BMI and smoking in adolescence and at the start of pregnancy and birth weight of the first-born child. METHODS: This longitudinal study included 1256 mothers, born 1962-1992, and their first-born children, born between 1982-2016. Self-reported questionnaire information on weight, height and smoking at age 19 was cross-linked with national register data obtained at the start of pregnancy and with the birth weights of the children. Univariable and multivariable linear regressions were performed to determine the impact of maternal factors at 19 years of age and at the start of the pregnancy respectively, and the importance of BMI status at these points of time for the birth weight of the first child. RESULTS: BMI and smoking at the start of the pregnancy displayed strong associations with birth weight in a multivariable analysis, BMI with a positive association of 14.9 g per BMI unit (95% CI 6.0; 23.8 p = 0.001) and smoking with a negative association of 180.5 g (95% CI -275.7; -85.4) p = 0.0002). Smoking and BMI at 19 years of age did not show this association. Maternal birth weight showed significant associations in models at both time-points. Becoming overweight between age 19 and the start of the pregnancy was associated with a significantly higher birth weight (144.6 (95% CI 70.7;218.5) p = 0.0002) compared to mothers with normal weight at both time points. CONCLUSIONS: Our findings indicate that the time period between adolescence and first pregnancy could be a window of opportunity for targeted health promotion to prevent intergenerational transmission of obesity.

Parental education and family income affect birthweight, early longitudinal growth and body mass index development differently.

AIM: This study investigated the effects of two parental socio-economic characteristics, education and income, on growth and risk of obesity in children from birth to 8 years of age. METHODS: Longitudinal growth data and national register-based information on socio-economic characteristics were available for 3,030 Swedish children. The development of body mass index (BMI) and height was compared in groups dichotomised by parental education and income. RESULTS: Low parental education was associated with a higher BMI from 4 years of age, independent of income, immigrant background, maternal BMI and smoking during pregnancy. Low family income was associated with a lower birthweight, but did not independently predict BMI development. At 8 years of age, children from less educated families had a three times higher risk of obesity, independent of parental income. Children whose parents had fewer years of education but high income had significantly higher height than all other children. CONCLUSION: Parental education protected against childhood obesity, even after adjusting for income and other important parental characteristics. Income-related differences in height, despite similar BMIs, raise questions about body composition and metabolic risk profiles. The dominant role of education underscores the value of health literacy initiatives for the parents of young children.