||In the international study depicted here, the negative
beta coefficients represent the decrease in blood pressure observed (per mmHg) for every
unit increase in birth weight (kg). As depicted, most study sites showed a negative
association, with the exception of the Nigerian population. However, given the wide
confidence intervals, the findings are very weak. In analyses of ponderal index in the
same study, a similarly weak inverse trend was noted for all countries except China which
did not show an inverse trend.
The genetic diversity represented in the populations
examined may contribute to the inconsistencies. Studies of black populations, for example,
have, in particular, shown inconsistencies in the relationship between birth weight and
blood pressure. It may also be possible that the inconsistencies in the literature are
attributed to the influences of unmeasured or unexamined effect modifiers. Finally,
childhood and the adolescent period may not be an optimal time for examining the fetal
origins of disease hypothesis. For example, differences in the timing of growth spurts
within and between study populations could add considerable "noise" to data.