In 1992 Carlsen et al. reported a significant global decline in sperm density between 1938 and 1990 [Evidence for Decreasing Quality of Semen during Last 50 Years. Br Med J 305:609-613 (1992)]. We subsequently published a reanalysis of the studies included by Carlsen et al. [Swan et al. Have Sperm Densities Declined? A Reanalysis of Global Trend Data. Environ Health Perspect 105:1228-1232 (1997)]. In that analysis we found significant declines in sperm density in the United States and Europe/Australia after controlling for abstinence time, age, percent of men with proven fertility, and specimen collection method. The declines in sperm density in the United States (approximately 1.5%/year) and Europe/Australia (approximately 3%/year) were somewhat greater than the average decline reported by Carlsen et al. (approximately 1%/year). However, we found no decline in sperm density in non-Western countries, for which data were very limited. In the current study, we used similar methods to analyze an expanded set of studies. We added 47 English language studies published in 1934-1996 to those we had analyzed previously. The average decline in sperm count was virtually unchanged from that reported previously by Carlsen et al. (slope = -0.94 vs. -0.93). The slopes in the three geographic groupings were also similar to those we reported earlier. In North America, the slope was somewhat less than the slope we had found for the United States (slope = -0.80; 95% confidence interval (CI), -1.37--0.24). Similarly, the decline in Europe (slope = -2.35; CI, -3.66--1.05) was somewhat less than reported previously. As before, studies from other countries showed no trend (slope = -0.21; CI, -2.30-1.88). These results are consistent with those of Carlsen et al. and our previous results, suggesting that the reported trends are not dependent on the particular studies included by Carlsen et al. and that the observed trends previously reported for 1938-1990 are also seen in data from 1934-1996.

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The question of declining sperm density revisited: an analysis of 101 studies published 1934-1996.

The antiestrogenic effect of cigarette smoking in women

Purpose: To review the current state of knowledge regarding risk factors for prostate cancer. Data Sources: Analysis of the literature through the use of MEDLINE as well as identification of papers...

Risk Factors for Prostate Cancer

A cohort of 17,633 white males age 35 and older responded to a mailed epidemiological questionnaire in 1966 and was followed until 1986 to determine the risk of cancer associated with diet, tobacco use, and other factors. During the 20-year follow-up, 149 fatal prostate cancer cases were identified. Relative risks for prostate cancer were significantly elevated among cigarette smokers (relative risk, 1.8; 95% confidence interval, 1.1–2.9) and users of smokeless tobacco (relative risk, 2.1; 95% confidence interval, 1.1–4.1). No significant associations were found with frequency of consumption of meats, dairy products, fruits, or vegetables. There were no overall significant associations between consumption of vitamin A from animal sources (retinol) and provitamin A from plant sources (carotene) and risk, but positive trends were seen for ages under 75, while inverse associations were found at older ages. Beverage consumption, including drinking coffee and alcohol, was unrelated to risk. Marital status, education, rural/urban status, and farming residence were also unrelated to the risk of fatal prostate cancer. The findings add to limited evidence that tobacco may be a risk factor for prostate cancer, but fail to provide clues to dietary or other risk factors.

https://cancerres.aacrjournals.org/content/canres/50/21/6836.full.pdf

Diet, tobacco use, and fatal prostate cancer: results from the Lutheran Brotherhood Cohort Study.

The present study examined lifestyle and behavioral correlates of the change in total testosterone over 13 years in 66 men aged 41-61 years who were former participants of the Multiple Risk Factor Intervention Trial (MRFIT) at the Pittsburgh, Pennsylvania, center. The authors also determined in these men if changes in total testosterone are related to changes in cardiovascular disease risk factors. The mean total testosterone level was 751 (standard deviation, 248) ng/dl at baseline and decreased by 41 (standard deviation, 314) ng/dl during follow-up. The correlation between measures was r = 0.44 (p < 0.001). In multivariate analysis, higher type A coronary-prone behavior score, greater pack-years of cigarette smoking, and the MRFIT special intervention group were associated with larger decreases in total testosterone. Age, body weight, weight change, leisure time activity level, and alcohol intake were not related to the change in total testosterone. The decrease in endogenous testosterone was associated with an increase in triglycerides and a decrease in high density lipoprotein cholesterol in multivariate analysis controlling for obesity and other lifestyle covariates. There was little relation between change in testosterone and change in total and low density lipoprotein cholesterol or blood pressure. This longitudinal study confirms a gradual decline in total testosterone levels with advancing age in older men and provides evidence that lifestyle and psychosocial factors are related to this decline. Decreases in endogenous testosterone levels with age in men are associated with potentially unfavorable changes in triglycerides and high density lipoprotein cholesterol.

/pdf/longitudinal-relation-between-endogenous-testosterone-and-nu35rmk1qh.pdf

Longitudinal Relation between Endogenous Testosterone and Cardiovascular Disease Risk Factors in Middle-aged Men A 13-Year Follow-up of Former Multiple Risk Factor Intervention Trial Participants

Kamal Zaki Mahmoud

Papers

Endocrine profile and semen characteristics in male smokers

Subfertility and varicocele. I. Venogram demonstration of anastomosis sites in subfertile men.

Comparative Value of Prostaglandin E1 and Papaverine in Treatment of Erectile Failure: Double-Blind Crossover Study among Egyptian Patients

Antisperm antibodies and human infertility

Experience with the classification, diagnosis, and therapy of nonejaculatory intercourse.