Introduction Observational studies, mainly from western populations, suggest that dairy product consumption is inversely associated with adiposity. However, in such populations, there is a limited range of dairy product intake while dietary intake and obesity share social patterning making evidence from non-western developed settings valuable in distinguishing whether the observed associations are biologically mediated or socially confounded.

Methods We used multivariable linear regression to examine the adjusted association of the frequency of milk or other dairy product consumption at 11 years with clinically measured body mass index (BMI) z-scores at about 13 years, relative to the 2007 WHO growth reference in a large (n=8327), population-representative Chinese birth cohort, comprising 88% of all births in Hong Kong in April and May 1997.

Results Of the original 8327 cohort members, 7933 are alive, participating and living in Hong Kong. At approximately 13 years, 7488 had clinically assessed BMI. Socio-economic position was positively associated with frequency of milk and other dairy product consumption. Neither milk nor other dairy product consumption was associated with BMI z-score (milk −0.02, 95% CI −0.06 to 0.03 and dairy products 0.03, 95% CI −0.01 to 0.07), adjusted for sex, mother's birthplace, highest parental education, pubertal stage, physical activity and other food consumption.

Conclusions In a non-western setting, milk and other dairy product consumption was not associated with adiposity, suggesting that any observed anti-obesigenic effects in western settings may be due to socially patterned confounding by socio-economic position.