CLIMATIC INFLUENCES ON HUMAN-BODY SIZE AND PROPORTIONS - ECOLOGICAL ADAPTATIONS AND SECULAR TRENDS

This study reevaluates the long-standing observation that human morpho logy varies with climate. Data on body mass, the body mass index [BMI; mass (kg)/stature (m)(2)], the surface area/body mass ratio, and rela tive sitting height (RSH; sitting height/stature) were obtained for 22 3 male samples and 195 female samples derived from studies published s ince D.F. Roberts' landmark paper ''Body weight, race, and climate'' i n 1953 (Am. J. Phys. Anthropol. 11:533-558). Current analyses indicate that body mass varies inversely with mean annual temperature in males (r = -0.27, P < 0.001) and females (r = -0.28, P < 0.001), as does th e BMI (males: r = -0.22, P = 0.001; females: r = -0.30, P < 0.001). Th e surface area/body mass ratio is positively correlated with temperatu re in both sexes (males: r = 0.29, P < 0.001; females: r = 0.34, P < 0 .001), whereas the relationship between RSH and temperature is negativ e (males: r = -0.37, P < 0.001; females: r = -0.46, P < 0.001). These results are consistent with previous work showing that humans follow t he ecological rules of Bergmann and Alien. However, the slope of the b est-fit regressions between measures of body mass (i.e., mass, BMI, an d surface area/mass) and temperature are more modest than those presen ted by Roberts. These differences appear to be attributable to secular trends in mass, particularly among tropical populations. Body mass an d the BMI have increased over the last 40 years, whereas the surface a rea/body mass ratio has decreased. These findings indicate that, altho ugh climatic factors continue to be significant correlates of world-wi de variation in human body size and morphology, differential changes i n nutrition among tropical, developing world populations have moderate d their influence. (C) 1998 Wiley-Liss, Inc.