The influences of childhood and adult socioeconomic position on body mass index: A longitudinal Swedish cohort study

Background: Low socioeconomic position (SEP) in adulthood has been associated with overweight and obesity in high-income countries. However, little is known about the contribution of childhood SEP to weight change. Using a Swedish general population sample, this study aimed to examine the association between five-year weight gain among adults and socioeconomic position in childhood and adulthood. Methods: The data was drawn from the Scania Public Health Cohort and included 4244 individuals (1816 males and 2428 females) between the ages of 29 and 60 years, stratified by sex and age (29-39 and 40-60 years). General linear and logistic regression models were used to analyse the data. Results: Adult SEP was inversely correlated to BMI at baseline in males and older females. Childhood SEP showed no clear pattern regarding current BMI or the risk of being overweight at baseline, either in males or females. However, BMI increase between baseline and follow-up was greater in the highest adult SEP groups than in lowest ones for both males and females, although with a weaker trend among females. High childhood SEP was associated with a greater BMI increase in older males, but the pattern was the opposite in older females. Conclusions: Adult as well as childhood SEP influences weight gains, but differently among males and females and in different age groups. The findings suggest two waves of socioeconomic weight gain patterns in the Swedish population: one across generations and another contemporary one.