Early life disadvantage and adult adiposity: tests of sensitive periods during childhood and behavioural mediation in adulthood

• Published in: International journal of epidemiology 2019-02, Vol.48 (1), p.98-107
• Main Authors: Gilman, Stephen E, Huang, Yen-Tsung, Jimenez, Marcia P, Agha, Golareh, Chu, Su H, Eaton, Charles B, Goldstein, Risë B, Kelsey, Karl T, Buka, Stephen L, Loucks, Eric B
• Format: Article
• Language: English
• Subjects: Absorptiometry, Photon; Adiposity; Adult; Body Mass Index; Child; Depression - epidemiology; Early Life Disadvantage and Child Health; Female; Humans; Infant, Newborn; Linear Models; Male; New England - epidemiology; Obesity - epidemiology; Obesity - etiology; Risk Factors; Social Class; Waist Circumference
• ISSN: 0300-5771; 1464-3685
• DOI: 10.1093/ije/dyy199

Abstract Background Early exposure to socioeconomic disadvantage is associated with obesity. Here we investigated how early, and conducted mediation analyses to identify behavioural factors in adulthood that could explain why. Methods Among 931 participants in the New England Family Study, we investigated the associations of family socioeconomic disadvantage measured before birth and at age 7 years with the following measures of adiposity in mid-adulthood (mean age = 44.4 years): body mass index (BMI), waist circumference and, among 400 participants, body composition from dual-energy X-ray absorption scans. Results In linear regressions adjusting for age, sex, race and childhood BMI Z-score, participants in the highest tertile of socioeconomic disadvantage at birth had 2.6 additional BMI units in adulthood [95% confidence interval (CI) = 1.26, 3.96], 5.62 cm waist circumference (95% CI = 2.69, 8.55), 0.73 kg of android fat mass (95% CI = 0.25, 1.21), and 7.65 higher Fat Mass Index (95% CI = 2.22, 13.09). Conditional on disadvantage at birth, socioeconomic disadvantage at age 7 years was not associated with adult adiposity. In mediation analyses, 10–20% of these associations were explained by educational attainment and 5–10% were explained by depressive symptoms. Conclusions Infancy may be a sensitive period for exposure to socioeconomic disadvantage, as exposure in the earliest years of life confers a larger risk for overall and central adiposity in mid-adulthood than exposure during childhood. Intervention on these two adult risk factors for adiposity would, if all model assumptions were satisfied, only remediate up to one-fifth of the excess adult adiposity among individuals born into socioeconomically disadvantaged households.