Early exposure to social disadvantages and later life body mass index beyond genetic predisposition in three generations of Finnish birth cohorts

Abstract

Background: The study aimed to explore the association between early life and life-course exposure to social disadvantage and later life body mass index (BMI) accounting for genetic predisposition and maternal BMI. Methods: We studied participants of Helsinki Birth Cohort Study born in 1934-1944 (HBCS1934-1944, n = 1277) and Northern Finland Birth Cohorts born in 1966 and 1986 (NFBC1966, n = 5807, NFBC1986, n = 6717). Factor analysis produced scores of social disadvantage based on social and economic elements in early life and adulthood/over the life course, and was categorized as high, intermediate and low. BMI was measured at 62 years in HBCS1934-1944, at 46 years in NFBC1966 and at 16 years in NFBC1986. Multivariable linear regression analysis was used to explore associations between social disadvantages and BMI after adjustments for polygenic risk score for BMI (PRS BMI), maternal BMI and sex. Results: The association between exposure to high early social disadvantage and increased later life BMI persisted after adjustments (β = 0.79, 95% CI, 0.33, 1.25, p < 0.001) in NFBC1966. In NFBC1986 this association was attenuated by PRS BMI (p = 0.181), and in HBCS1934-1944 there was no association between high early social disadvantage and increased later life BMI (β 0.22, 95% CI-0.91,1.35, p = 0.700). In HBCS1934-1944 and NFBC1966, participants who had reduced their exposure to social disadvantage during the life-course had lower later life BMI than those who had increased their exposure (β − 1.34, [− 2.37,-0.31], p = 0.011; β − 0.46, [− 0.89,-0.03], p = 0.038, respectively). Conclusions: High social disadvantage in early life appears to be associated with higher BMI in later life. Reducing exposure to social disadvantage during the life-course may be a potential pathway for obesity reduction.

Understanding the cumulative risk of maternal prenatal biopsychosocial factors on birth weight: a DynaHEALTH study on two birth cohorts

“…25 It is important to note, however, that individual’s psychological well-being partly depend on the social environment we live in. 26 We observed a positive association between ‘ Factor1-BMI ’ and birth weight, consistent with observational studies. 27 28 Tyrell et al demonstrated a positive causal genetic association between maternal BMI and birth weight.…”

Obesity Prediction in Young Adults from the Jerusalem Perinatal Study: Contribution of Polygenic Risk and Early Life Exposures

“…However, using a stratified sampling approach and over-sampling in the ends of the distribution ensured that offspring with a full range of mppBMI and birth weight were included in our study. Second, while the PRS explained only a modest percent of the variation for BMI, this is similar to other studies and expected with the current methodology used (15, 35). Third, both mppBMI and GWG were reported by mothers in interviews conducted by nurses while hospitalized after delivery.…”

“…Parental ages and socioeconomic status (SES) determined by parents’ occupation were not associated with offspring’s BMI at age 32 and their inclusion in the model didn’t change the regression coefficient for PRS. In a study spanning three generations in Finland, early-life social disadvantages related to later-life BMI, but this association weakened when accounting for PRS (35). Interestedly, in the youngest cohort included in the study, the association between early social disadvantage and later life BMI was attenuated after adjusting for PRS.…”

Socioeconomic differences in the association between maternal age and maternal obesity: a register-based study of 707,728 women in Finland

“…health outcomes. This triggering point of poor health outcomes could be shorter among women of lower socioeconomic status due to a high level of chronic exposure to obesity risk factors from the sensitive teenage period, and because women with lower socioeconomic status are more vulnerable to these risk factors than women in high socioeconomic groups [16][17][18]. Among upper-level employees, the association between maternal age and maternal obesity across all age groups was weaker than that of other socioeconomic groups.…”