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Background
Different approaches have been used to test life course models of socioeconomic position (SEP) in relation to cardiovascular disease (CVD) but have generally only tested one model.
Objective
We describe a series of nested life course models that correspond to the critical period, accumulation, and social mobility models and test them simultaneously, on multiple CVD risk factors in, a large cohort study.
Design
Prospective birth cohort study.
Setting
England, Scotland, and Wales.
Participants
5362 singleton births in the MRC National Survey of Health and Development, followed up since their birth in 1946.
Main Outcomes
CVD risk factors at 53 years: body mass index (BMI), systolic and diastolic blood pressure, total cholesterol, low-density lipoprotein, high-density lipoprotein, triglycerides, glycated haemoglobin (HBA1c).
Results
Social class, according to the Registrar General’s classifications, at 3 time points were utilised: childhood (father’s occupation when cohort member was age 4), early adulthood (own occupation at age 26 years), and later adulthood (own occupation at 43 years). Partial F-tests comparing a saturated model with each simpler life course model were used to identify the most appropriate model for each risk factor. For women, SEP generally affected the CVD risk factors in a cumulative manner; while SEP in childhood was the prominent model for men. For example, in women BMI increased by 1.11 kg/m2 (95% CI 0.76 to 1.46) per unit increase in SEP accumulation score. In men BMI was 0.42 kg/m2 (0.17 to 0.68) higher in those from a manual social class in childhood. In both genders, a late adulthood critical period for HBA1c was the best fitting model. BMI at age 53 reduced the associations for all outcomes but whereas BMI at age 53 captured women’s lifetime BMI trajectory, it was men’s BMI at earlier ages that explained more of the association than BMI at older ages. Exercise, total energy and fat intake, and menopausal status (women only) attenuated the SEP/BMI association in both genders, while lifetime smoking pattern increased the association in women (regression coefficients final model: women 0.77 kg/m2 (0.39 to 1.15) and men 0.75 kg/m2 (0.16 to 1.35).
Conclusion
SEP across life influences CVD risk factors differently in men and women. Health behaviours may influence BMI and subsequently the other CVD risk factors, but at different points in the life course depending on gender. Gender difference in health behaviours, reproductive characteristics, and social roles across life may explain the differential effects of SEP on CVD risk factors.