An unresolved question arising from human evolutionary research relates to the function of the postreproductive period in human females. If menopause is not merely an artifact resulting from the benefits of civilization, there must be an adaptive mechanism favoring the offspring of women who continue to thrive well past the time of their last ovulation. The "grandmother hypothesis" was developed on the basis of the original suggestion by Williams (1957 Evolution 11:32-39) that "stopping early" would benefit already-born children. This idea, combined with the concepts of kin selection (Hamilton 1964 J Theor Biol 7:1-52) and parental investment (Trivers 1972 Sexual Selection and the Descent of Man, Chicago: Aldine, p. 136-179), was expanded to suggest that postreproductive women (in contrast to males) contribute to their inclusive fitness by extending support to their grandchildren. We used discrete time event history analysis (Allison [1984] Event History Analysis, Newbury Park: Sage; Allison [1995] Survival Analysis, Cary, NC: SAS Institute) and logistic regression on data provided in population registers (Shūmon Aratame Chō, or SAC) from a village in central Japan, covering the period from 1671-1871, in a preliminary investigation of the effects of household grandparental presence on the probability of a child's death. We found that after accounting for the presence of other household members, the only grandparent whose presence exerted a consistent negative effect on the likelihood of a child's death was the mother's mother. Due to the small sample size of households that contained maternal grandmothers, these results failed to achieve statistical significance. Their importance, however, is in what they suggest about future research, i.e., census data from preindustrial societies can provide a basis for testing evolutionary proposals, including the "grandmother hypothesis."
Dermatoglyphic prints and salivary samples were taken on a sample of 39 adult males. A statistical relationship between dermatoglyphic asymmetry and adult testosterone levels as measured in saliva was examined for seven dermatoglyphic variables by means of correlation, regression, and analysis of covariance, controlling for age and stature when necessary. The first two types of analyses indicated a significant effect of testosterone level upon the asymmetry of three dermatoglyphic variables: a-b ridge count, palmar pattern intensity, and the combined pattern intensity of palm and digits. Analysis of covariance, which examined the effect of testosterone level as a categorical variable, while holding age or stature constant, demonstrated the asymmetry of five variables to be significantly affected by testosterone level: radial digital count, digital pattern intensity, palmar pattern intensity, total digital ridge count, and the combined palmar and digital intensity. Although there is as yet only associational evidence linking levels of prenatal and secondary testosterone, the results of the present study lend support to the hypothesis that prenatal testosterone levels may have a significant effect on the development of dermatoglyphics.
Interferon-alpha-2a is active against some childhood craniopharyngiomas; its toxicity precludes administration of high daily doses, and the optimum dose level and schedule remain to be defined.
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This study investigates the relationship between work and ill health resulting from stressors originating in the work environment. The association between work and health has been well-documented. Factors in the work environment leading to ill health have included generalized psychological stress and/or specific physical environmental characteristics. Data for this study come from a 1998 telephone survey, the Indiana Survey of Work in a Polarized Economy, under the auspices of the Center for Survey Research at Indiana University. The dependent variable is an index that measures ill health among workers; control variables include sociodemographic and lifestyle characteristics of these workers as well as their job characteristics; and the four key independent variables are occupational status, organizational disruption, layoff experience, and educational discordance of the workers. Multiple regression analysis on the entire sample (n = 919) demonstrates that occupational status is negatively associated with ill health, while organizational disruption, layoff experience, and educational discordance are positively associated with it. Separate analyses for male (n = 474) and female (n = 445) respondents find significant sex differences in the effects of the key variables: for males, organizational disruption is positively related to ill health while for women occupational status is negatively related and layoff experience and educational discordance are positively related to ill health. The findings from the present research provide insight into the interrelationship of occupational environment and health within the framework of evolutionary medicine.
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