Sperm quality of healthy smokers, ex-smokers, and never-smokers

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1 FERTILITY AND STERILITY Copyright 1986 The American Fertility Society Vol. 45, No.1, January 1986 Printed in U.SA. Sperm quality of healthy smokers, ex-smokers, and never-smokers Hermann-J. VOgt, M.D.*t Wolf-D. Heller, Dr. rer. pol.:j: Siegfried Borelli, M.D., Ph.D.* Dermatologische Klinik und Poliklinik der Technischen Uniuersitdt Munchen, Munchen, and institut fur Statistik und Mathematische Wirtschaftstheorie, Uniuersitdt Karlsruhe, Karlsruhe, Federal Republic of Germany The possible effects of cigarette smoking on sperm quality were investigated in a blind study of 333 healthy male volunteers 19 to 40 years of age. All subjects with clinically proven abnormalities, operations, or inflammatory diseases of the genital organs, exposure to radiation exceeding routine x-ray examination, or medication were excluded, and the data from 150 smokers, 37 ex-smokers, and 52 never-smokers were evaluated. There was a small but insignificant decrease in sperm density from neversmokers to ex-smokers and to smokers. Eight smokers (6%) had sperm counts < 1 x 10 6 /ml, whereas none of the ex-smokers or never-smokers fell into this category. This difference, however, is not statistically significant (P = 0.084). No statistically significant effect of smoking habits on sperm density, motility, and morphologic features was detected. It is concluded that smoking does not affect the motility and morphologic features of sperm in healthy adult men. The diminished sperm density in heavy smokers may be related to factors associated with smoking. Fertil Steril45:106, 1986 The possible effect of men's smoking on fertility and progeny has been intensively investigated,i-14 but the findings present a picture that is far from conclusive. To obtain unbiased results, we (1) performed our study under totally blind conditions; (2) used healthy volunteers in their procreative age, rather than patients attending infertility clinics; and (3) took into consideration Received April 11, 1985; revised and accepted September 23,1985. *Dermatologische Klinik und Poliklinik der Technischen Universitat Miinchen. treprint requests: Hermann-J. Vogt, M.D., Dermatologische Klinik und Poliklinik der Technischen Universitat Miinchen, Biedersteiner Str. 29, D-8000 Miinchen 40, Federal Republic of Germany. :j:institut fiir Statistik und Mathematische Wirtschaftstheorie, Universitat Karlsruhe. 106 Vogt et al. Sperm quality and smoking factors interfering with smoking and spermatogenesis. MATERIALS AND METHODS Three hundred thirty-three healthy men, 19 to 40 years of age, mostly students (70%), volunteered to take part in a study that comprised the delivery of single specimens of ejaculate and blood, a clinical examination concentrating on the genital organs, and the completion of a questionnaire on medical history, sexual behavior, exposure to radiation, smoking, drinking, and drug habits. Subjects were classified as smokers if they claimed to have smoked regularly (at least one cigarette per day, with the lowest reported consumption nine cigarettes per day) for at least 1 year before their examination, as ex-smokers if they had smoked regularly for 1 year but had

2 stopped at least 1 year before their examination, and as never-smokers if they had never smoked regularly throughout their life. The subjects were instructed to abstain from sexual activity for 5 days before giving their specimen of ejaculate. Blood samples were taken between 8:30 A.M. and 10:00 A.M. The ejaculate specimen was obtained by masturbation in the clinic. The subjects received a small payment on completion of the examination, as well as information about the andrologic findings, if they so desired. All examinations were carried out in the dermatologic outpatient department, University of Munich, Federal Republic of Germany, without knowledge of the subjects' smoking habits (blind study). The volume of the ejaculate was measured on the graduated scale of the collection vessel. The ph value was measured with special indicator paper (6.6 to 8.0) manufactured by E. Merck, Darmstadt, FRG. Sperm motility was determined by putting liquefied ejaculate on a slide with a loop and placing a cover glass on top. The percentage of motile sperm and the quality of motility were recorded within approximate limits. If < 50% of the sperm were motile, an eosin test (vitality test) was carried out. An exact sperm count was conducted with a hemocytometer. If no spermatozoa were found, the ejaculate was centrifuged and the sediment again subjected to microscopic examination. Cytomorphologic differentiation of the cells was carried out by preparing a smear in the same way as a blood smear, fixing it with methanol, and staining it with hematoxylin and eosin. The proportion of misshapen spermatozoa was expressed as a percentage. For each patient, the total number of cells, including morphologically normal cells, added up to 100%. The concentration of fructose in the seminal plasma was determined with the method developed by Nennstiel and Alich. 15 The testosterone (T) concentration in the serum was determined by radioimmunoassay with the technique developed by Pirke. 16 The coefficient of variation in the series was 7% at a mean concentration of 579 ng/100 ml. The concentration of luteinizing hormone (LH) and follicle-stimulating hormone (FSH) in the serum each was measured in one step with radioimmunoassay packs (Serono, Freiburg im Breisgau, FRG). The double-antibody method was used. The variance of LH in the series was 8.2% at a mean concentration of 4.7 mulml and offsh was 9.0% at a mean concentration of 4.9 mu/ml. Vol. 45, No.1, January.1986 Differences between never-smokers, ex-smokers, and smokers were checked for significance with the use of, as appropriate, analysis of variance, Student's t-test, Mann-Whitney U-test, or chi-square test. RESULTS Of the 333 subjects investigated, 239 were evaluated. The other subjects were excluded because of clinically proven abnormalities in the genital region, operations or inflammatory diseases of the genital organs, exposure to radiation exceeding routine x-ray examination, or medication. Significantly more never-smokers and exsmokers than smokers (P = 0.036) were excluded because ofvaricoceles. All other exclusion criteria were of minor importance and showed no significantly different frequencies in the groups investigated. The smokers, ex-smokers, and never-smokers showed no significant differences with respect to age, weight, height, family status, and fertility in terms of number of children. "Heavy" drinking (> 50 gm ethanol/day) and consumption of hallucinatory drugs were significantly more common. among the smokers than among ex-smokers and never-smokers. Sexual habits and the results of the hormone and spermatologic analyses are summarized in Table 1. Smokers, ex-smokers, and never-smokers revealed no significant differences in their sexual habits. There is a trend toward an increased frequency of coitus in smokers and exsmokers, but adding up group averages for masturbation and coitus, the average number of ejaculations per month is 17.5, 17.7, and 16.3 for smokers, ex-smokers, and never-smokers, respectively. Smokers showed significantly higher blood T levels than never-smokers, with the level for ex-smokers intermediate between these two groups. In the group of smokers, the serum T level was positively correlated with daily cigarette consumption (P < 0.02). No differences were found for LH and FSH blood levels. Sperm density showed a tendency to decrease from never-smokers to ex-smokers and to smokers. In the group of smokers, the sperm density was inversely correlated with daily cigarette consumption. The linear trend was significant at the 5% level. However, the difference between smokers and never-smokers only comes close to signifi- Vogt et al. Sperm quality and smoking 107

3 Table 1. Sexual Habits and Results of Hormone and Spermatologic Analysis a Never-smokers Ex-smokers Smokers Smoking categories (cigarettes/day).; No. of subjects Age (yrs) 25.0 ± ± ± ± ± ± 0.8 Sexual habits Frequency of masturbation 8.4 ± ± ± ± ± ± 1.9 (per month) Frequency of coitus (per 7.9 ± ± ± ± ± ± 1.5 month) Hormones T (flg/d 6.63 ± ± ± ± ± ± 0.53 LH (mu/md 6.5 ± ± ± ± ± ± 0.54 FSH (mu/md 3.1 ± ± ± ± ± ± 0.34 Ejaculate Volume (m!) 4.2 ± ± ± ± ± ± 0.45 ph 7.49 ± ± ± ± ± ± 0.06 Fru~tose (mg/ml) 2.26 ± ± ± ± ± ± 0.23 Density (10 6 /md 72.9 ± ± ± ± ± ± 10.5 Motility after 10 minutes (%) 74 ± ± ± ± ± ± 2.9 Morphologic features Normal spermatozoa (%) 68.0 ± ± ± ± ± ± 2.8 Young forms (%) 6.8 ± ± ± ± ± ± 1.2 Old forms (%) 7.4 ± ± ± ± ± ± 1.6 Degenerate forms (%) 17.8 ± ± ± ± ± ± 2.2 amean ± standard error of the mean. Smokers versus ex-smokers versus never-smokers, T: overall, P < 0.04; linear trend, P < Never-smokers: T: overall, P < 0.06; linear trend, P < Sperm density: overall, P < 0.23; linear trend, P < cance (P = 0.07). The sperm density was found to be inversely correlated with serum T levels in all groups observed, with the correlation significant in the group of current smokers (r = , P < 0.05). After excluding smokers, ex-smokers, and never-smokers who reported drinking > 50 gm ethanol/day and/or taking drugs, we obtained sperm densities of 62.8, 65.5, and 70.4 x lo6/ml, respectively. Comparing the alcohol drinkers and/or drug users and those who are neither among the smokers with their counterparts in the groups of ex-smokers and never-smokers, we found no significant differences in sperm density. Nine heavy smokers (;?! 26 cigarettes/day) who reported drinking > 50 gm ethanol and/or taking drugs showed a sperm density of 27.8, compared with 53.7, x 106/ml in 14 heavy smokers who reported drinking less alcohol and/or taking no drugs. The difference between these two groups is not significant. Four smokers (3%) showed "cryptozoospermia" «1 X 106 sperm/md and another four smokers had "azoospermia" (no sperm), whereas neither of these deficiencies was found among the ex-smokers or never-smokers. The difference is not statistically significant (P = 0.08). No statistical significances were seen with respect to motility and morphologic features of sperm. DISCUSSION It was our aim to determine whether the noxae in tobacco smoke affect sperm quality in healthy men in their procreative years. We consider our procedure superior to investigating infertility clinic patients, even though our group was selfselected and student-oriented. Our spermatologic analysis revealed no statistically significant differences between smokers, ex-smokers, and never-smokers. The sperm density shows a tendency to decrease from never-smokers to ex-smokers and to smokers; it is lowest in the group of heavy smokers, thus appearing to confirm the results reported by Viczian,4 Vogel et al} Stekhun,6 and Handelsman et al. 13 However, the lower sperm count in smokers might in part be because a number of subjects drank "heavily" and/or took hallucinatory drugs. Unfortunately, the effect of alcohol and/or drugs could not be separated from smoking, because among the nonsmokers or exsmokers there were only six subjects (11.5%) who reported heavy drinking and/or taking hallucinatory drugs. Another reason for a lower sperm density in smokers is that eight subjects with azoospermia and cryptozoospermia were included in this group. After excluding these cases, the sperm density in medium smokers (16 to 25 cigarettes/ day) and in heavy smokers (26+ cigarettes/day) 108 Vogt et al. Sperm quality and smoking

4 increased to 67.0 ± 6.0 and 50.0 ± 11.3 x 106/ml, respectively. That four smokers had azoospermia and four had cryptozoospermia might indicate that smoking exerts an effect on an already impaired spermatogenesis. This would be in line with an individual sensitivity to tobacco smoke, as discussed by several investigators.4, 7 In our study, however, the azoospermia may be caused by factors other than smoking. Three of these four patients with azoospermia had normal testes volumes and normal FSH levels, which indicates an obstructive azoospermia. The fourth patient had a decreased testicular volume (14 ml for either the right or left testis) and a highly elevated FSH levels (18.5 mufml). This suggests that a primary hypogonadism or a Sertoli-cell-only syndrome was the cause of the observed azoospermia. The same might be true for at least one smoker with cryptozoospermia (testes volume: left, 15 ml; right, 14 ml; FSH level, 8.1 mufml). Indeed, there might be further causes of the lower sperm density in heavy smokers, compared with never-smokers. According to Malcolm and Shepard,17 smokers might have an increased level of sexual activity, possibly due to their elevated serum T levels, found in our study and several others It has been suggested that serum T levels are correlated with sexual activity.21 We must consider that reports on sexual habits are not necessarily as reliable as they should be to drawn scientific conclusions. Our data, which do not support the findings of Malcolm and Shepard,17 may suffer from this limitation. Another uncertainty may be the required abstinence from sexual activities for 5 days before the investigation. Sperm motility is another important index of fertility. No differences in sperm motility were found between smokers, ex-smokers, and neversmokers. This is in contrast to the findings of Vogel et ai.,2 Viczian,4 Stekhun,6 Evans,22 and Handelsman et ai.,13 but in accordance with the results of Rodriguez-Rigau et ai.lo and Osser and Liedholm.14 Beyond sperm density and motility, sperm morphologic features is the third major criterion for fertility. Again, no differences were found between smokers, ex-smokers, and never-smokers, which confirms the results of Rodriguez-Rigau,lO Nebe and Schirren/ Godfrey,9 Handelsman et ai.,13 and Osser and Liedholm,14 but conflicts with those ofviczian4 and Evans et ai.8 The study by Viczian4 is not suitable, in our view, as a basis for comparison of smokers and nonsmokers, because the smokers were selected from a group of patients with fertility disorders, whereas the nonsmokers were without exception the fathers of healthy children. We have no explanation for the conflicting findings with respect to sperm morphologic features in the study of Evans et al.,8 compared with that of Godfrey9 and our study, even though these three studies were performed blindly and nearly the same exclusion criteria were used. Based on the analysis of our data, differences in smoking duration, which cannot be excluded because of lacking details in the study by Evans et ai.,8 do not explain the reported differences in sperm morphologic features in their and our study. Evans et ai.8 found no association between degree of sperm abnormality and number of cigarettes smoked. In contrast to Vogel et ai. 2 and Klaiber et al} we found more never-smokers (24.4%) and exsmokers (23.6%) than smokers (14%) with varicoceles. We regard their and our results as pure chance findings, because Ducot et ai. 23 and Handelsman et ai. 13 found no influence of smoking on this parameter. Our FSH and LH levels agree with those of Persky et ai.,24 Winternitz and Quillen,25 and Handelsman et ai.,13 who found no differences between smokers and nonsmokers. Our results of raised T levels in smokers are supported by those of Dotson et ai./8 Gutai et ai./9 and Dai et ai. 20 and are contrary to those of Briggs.1 Handelsman et ai. 13 found equal levels of plasma T in smokers and nonsmokers. Probably the observed difference in T levels is the expression of a personality difference between smokers and nonsmokers, which can also, for instance, be deduced from their significantly different alcohol and drug use habits. However, all recorded T concentrations were within normal limits. We conclude that cigarette smoking has no effect on motility and morphologic features of sperm in healthy adult men between 20 and 40 years of age. The marginal differences we found for sperm density are probably without any biologic significance for fertility and may be attributed more to factors other than smoking. Acknowledgment. We wish to thank Professor Schievelbein (Deutsches Herzzentrum Miinchenl for recruiting the subjects and recording their smoking habits. His cooperation, which enabled us to perform the study under blind conditions, is gratefully acknowledged. Vol. 45, No.1, January 1986 Vogt et al. Sperm quality and smoking 109

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