Background:Obesity levels are increasing in many countries. It has been suggested that increasing obesity levels in young women lead to intra-uterine environments that, in turn, stimulate increased obesity among their offspring, generating the intergenerational acceleration of obesity levels. If this mechanism is of importance the association of maternal body mass index with offspring body mass index should be stronger than the association of paternal and offspring body mass indices. Objective:To compare the relative strengths of association of maternal and paternal body mass index with offspring body mass index, taking into account the possible effect of non-paternity.
Methods:We compared strength of association for maternal-offspring and paternal-offspring BMI for 4,654 complete parent-offspring trios in the Avon Longitudinal Study of Parents and Children (ALSPAC), using unstandardized and standardized regression analysis. We carried out a sensitivity analysis to investigate the influence of non-paternity on these associations.
Results:The strength of association between parental BMI and BMI of offspring at age 7½ was similar for both parents. Taking into account correlations between maternal and paternal BMI, performing standardized rather than instandardized regression and carrying out a sensitivity analysis for non-paternity emphasised the robustness of the general similarity of the associations. The associations between high parental BMI (top decile) and the BMI of their offspring are also similar for both parents.
Conclusion:Comparison of mother-offspring and father-offspring associations for body mass index suggest that intergenerational acceleration mechanisms do not make an important contribution to levels of childhood BMI within the population. Associations at later ages and for different components of body composition now require study.