Citation

Smolensky MH, Reinberg A, Bicakova-Rocher A, Sanford J. Chronobiologia 1981; 8(3): 217-230.

Copyright

(Copyright © 1981, Associated Chronobiologia Researchers)

DOI

unavailable

PMID

7307715

Abstract

This study analyzes police and city health records to investigate the seasonal variation of rape and of venereal disease in Houston, Texas and in Paris, France. Rape data were available for both cities, while venereal disease data were available only for the city of Houston. Monthly data were averaged and plotted in the form of an annual chronogram, and both the conventional and the cosinor methods were used to measure the amplitude of the seasonal variation. Between 1973-74 there were 836 reported rapes in Paris; between 1974-75 there were 1133 reported rapes in Houston. Inspection of the plot for Paris reveals considerable monthly variations with a peak in August and a trough in February; for Houston the monthly variation revealed a peak around August and a trough in March-April. Even though the overall yearly totals of reported rape differ by 4-fold between the 2 cities, the amplitude values of the circannual rhythms are nearly identical, i.e. 21.6% for Paris and 21.4% for Houston. From January 1970-May 1979 there were 3024 cases of primary syphilis and 179,004 cases of gonorrhea in Houston clinics. For syphilis the plot suggests a major peak in detection around December and a trough in July, and for gonorrhea a peak in August and a trough in March, or a circannual acrophase of August 5, with the 95% CI from July 6-September 4 for gonorrhea, and a circannual acrophase of November 7, with the 95% CI from October 10-December 3 for primary syphilis. Previous studies have revealed a seasonality in the occurrence of rape with peaks in late summer or early fall. Exogenous factors, such as the choice of clothing and the type of outdoor activities, may help in explaining the seasonality of rape, but the influence of endogenous factors, such as increased testosterone and prolactin levels in males, upon human sexual activity seems to be much more important. There is strong evidence to suggest that man is a seasonal breeder, becoming more active during the portion of the year when the photoperiod is short.

Language: en