Taller mothers are more likely to have children who are healthier ? indeed, their children are more likely not just to thrive, but to survive ? compared to children of shorter mothers. The findings come from a massive new study of millions of children in low- and middle-income countries.
"The key finding of this paper was to show a consistent association between maternal height and offspring health, which was mainly defined in terms of offspring mortality by age five and the risk of experiencing a failure in growth," says S.V. Subramanian of the Harvard School of Public Health. He is the lead author of the study, published this week in JAMA, the journal of the American Medical Association.
A mother's height reflects a lifetime of nutritional and social factors that can influence her health and, thus, growth.
Subramanian and his colleagues combined the results of more than 100 separate surveys in 54 countries. Previous studies found that a mother's height could predict infant mortality and other conditions right around the time of birth. But this study considered the health of children up to age five, as measured by weight, growth and survival.
"I think this was among the first studies to show that the effect of shorter height is kind of long-lasting. It certainly goes into infancy and childhood," Subramanian says.
Lots of factors determine whether a child survives and thrives through the first years of life, but Subramanian says if you want to look at one simple predictor, the mother's height is it.
"For growth failure, height is the most important factor, the most important. More than the wealth of the household for the child. More than the education of the mother."
And the relationship was seen consistently in almost every country Subramanian reviewed.
"The association ? and to some extent also the strength of the association ? does not seem to vary. In 52 out of 54 countries, we find the same association."
The two exceptions, incidentally, were Gabon and Comoros.
The Harvard researcher says that while the association is clear, the 'why' still needs more work.
"At this point we haven't quite put our hands on what could be the precise mechanisms through which they're occurring, this association, but this certainly provides [a] solid framework to now focus on what are the different mechanisms through which height could influence offspring health, certainly into infancy and childhood."
Subramanian says the study highlights the long-term effects of factors that contribute to development, such as nutrition, literacy and social environment. It suggests that the environment in which a girl grows up can affect the health of her child a decade or more later, as the child grows up.