Child physical development in the UK: the imprint of time and socioeconomic status.

Summary Objectives Social health inequalities remain a key policy challenge. The existing literature has not presented a synthetic view on the evolution of inequalities in physical development across childhood. We examine social disparities as children grow older using a range of different outcomes. Study design Population-based secondary data analysis. Methods We employ longitudinal data on British children aged 9 months to 12 years from the Millennium Cohort Study (n = 13,811–18,987) and focus on multiple child physical measures: weight, body mass index (BMI), overweight, fat mass and waist circumference. Results Higher family income is associated with lower BMI (for females), less body fat and a smaller likelihood of overweight (for both genders) on average throughout childhood. When income is multiplied by 3, the probability of overweight decreases by 2.8 (95% CI −0.041 to −0.016) percentage points for females and by 2.7 (95% CI −0.038 to −0.