Temperature oscillations may shorten male lifespan via natural selection in utero
Much literature argues that natural selection has conserved mechanisms that spontaneously abort fetuses, particularly males, least likely to survive in prevailing environmental conditions including cold ambient temperature. These reports imply the hypothesis that males in gestation during relatively warm periods who confront relatively cold climates in early life live, on average, shorter lives than other males. We estimate the effect of warm-to-cold temperature shifts on the observed lifespan at age one of males born in Sweden from 1850 through 1915. We test this hypothesis using annual cohort lifespan at age 1 year for Swedish males from 1850 to 1915. For our independent variable, we score a series “1” for birth cohorts that experienced relatively warm temperatures in utero but relatively cold temperatures from age 1 through 4 years, and “0” for other cohorts. We use time-series methods, which adjust the data to remove autocorrelation, to estimate the association between these variables. Consistent with theory, males in gestation during relatively warm times who encounter relatively cold temperatures in early life have a shorter lifespan than other males. The association survives adjustment for the longevity of females as well as the main effect of temperatures during gestation and early life. Our findings imply that the increased frequency and amplitude of temperature shifts expected from climate change could influence which humans survive gestation and how long they live.
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- Box G, Jenkins G, Reinsel G (1994) Time series analysis: forecasting and control. Prentice Hall, LondonGoogle Scholar
- Kelsey RM, Alpert BS, Patterson SM, Barnard M (2000) Racial differences in hemodynamic responses to environmental thermal stress among adolescents. Circulation 101:2284–2289Google Scholar
- Lee TM, Zucker I (1988) Vole infant development is influenced perinatally by maternal photoperiodic history. Am J Physiol Regul Integr Comp Physiol 255:R831–R838Google Scholar
- Parry M, Canziani O, Palutikof J, van der Linden P, Hanson C (eds) (2007) Climate change 2007: impacts, adaptation and vulnerability. Contribution of Working Group II to the Fourth Assessment Report of the Intergovernmental Panel on Climate Change. Cambridge University Press, Cambridge, UK, p 1000Google Scholar
- Saadat M (2008) Decline in sex ratio at birth after Bam (Kerman Province, Southern Iran) earthquake. J Biosoc Sci 40:935–937Google Scholar
- Schön L (2008) Sweden—economic growth and structural change, 1800–2000. In: Whaples R (ed) EH.Net EncyclopediaGoogle Scholar