[A case-control study of dangerous factors related to infertility]

This paper reports the case-control study of dangerous factors related to infertility in Henan province during 1987-1988. There were two groups. One was a primary infertility group with 319 couples. The other was a normal fertility group with 714 couples, who were neighbours of the first group, among whom the women's age range was within 6 years old. The survey materials were analyzed by SAS programmes in the computer. The methods of analysis were single factor and logistic regression analysis of factors. The results of single factor analysis showed that in male, infertility had a close relationship with eating edible rude cotton seed oil; suffering from Varicocele; hydrocele of tunica vaginalis; sex dysplasia; breast dysplasia; puberty enuresis; parotitis after puberty; familial infertility and working under high temperature conditions. In female, menstrual disorder; a sexuality or pain during coitus; familial infertility; TB and other chronic diseases might be major contributors to the incidence of infertility. The results of logistic regression analysis of the factors related to infertility suggested that in male, eating edible rude cotton seed oil, suffering form varicocele; sex dysplasia; puberty enuresis; and in female, menstrual disorder; TB; consanguineous marriage, lower rate of coitus, frequent contact with pernicious substances might be major dangerous factors causing infertility. The results of the logistic regression analysis were different from those of the single factor analysis because the former not only analyzed the major influence of each factor but also considered the comprehensive effects of the relevant factors.