Season of Birth and Human Longevity

Summary: Adult women over thirty live three years longer if they were born in May or December, rather than in August.

Interestingness: 2

Paper by Leonid A Gavrilov and Natalia S Gavrilova in the Journal of Anti-Aging Medicine, Volume 2, Issue 4, Winter 1999.

(((
Short two-page paper analysing a subset of the same data they used for their longevity vs fertility paper, ie European aristocratic families. In this case, they analysed a lot of variables until they found one that correlated with longevity.

On the relevant subsample of 4911 women, adult women over 30 born between 1800 and 1880 lived shortest if they were born in August and longest if they were born in May with the difference at about three and a half years. This is after correcting for a whole heap of variables that have nothing to do with month of birth but are related to longevity: year of birth, maternal and paternal life spans, age of parents at birth, birth order, nationality, whether the death was violent, loss of either or both parents before age twenty.

They have a graph and it doesn't look good to me. The only reasons I can think of, and that they propose, for the effect would be availability of vitamins (or calories but they are unlikely to be a problem for this group since they were all from aristocratic families) at specific points in the pregnancy or early life, but the graph is very noisy and it mostly jumps up and down. For example, the difference between July and August births is two and a bit years, and between August and September the difference is about a year and a half, with August at the minimum. The other bad months are February and March, on the other side of the year, with women born then living about a year longer than those in August. If the effect is real, then the critical periods during pregnancy must be very short.

I'm not buying any of it until it gets replicated.
)))