Cecilia Høst Ramlau-Hansen

BMI in relation to sperm count: an updated systematic review and collaborative meta-analysis

BACKGROUND The global obesity epidemic has paralleled a decrease in semen quality. Yet, the association between obesity and sperm parameters remains controversial. The purpose of this report was to update the evidence on the association between BMI and sperm count through a systematic review with meta-analysis. METHODS A systematic review of available literature (with no language restriction) was performed to investigate the impact of BMI on sperm count. Relevant studies published until June 2012 were identified from a Pubmed and EMBASE search. We also included unpublished data (n = 717 men) obtained from the Infertility Center of Bondy, France. Abstracts of relevant articles were examined and studies that could be included in this review were retrieved. Authors of relevant studies for the meta-analysis were contacted by email and asked to provide standardized data. RESULTS A total of 21 studies were included in the meta-analysis, resulting in a sample of 13 077 men from the general population and attending fertility clinics. Data were stratified according to the total sperm count as normozoospermia, oligozoospermia and azoospermia. Standardized weighted mean differences in sperm concentration did not differ significantly across BMI categories. There was a J-shaped relationship between BMI categories and risk of oligozoospermia or azoospermia. Compared with men of normal weight, the odds ratio (95% confidence interval) for oligozoospermia or azoospermia was 1.15 (0.93-1.43) for underweight, 1.11 (1.01-1.21) for overweight, 1.28 (1.06-1.55) for obese and 2.04 (1.59-2.62) for morbidly obese men. CONCLUSIONS Overweight and obesity were associated with an increased prevalence of azoospermia or oligozoospermia. The main limitation of this report is that studied populations varied, with men recruited from both the general population and infertile couples. Whether weight normalization could improve sperm parameters should be evaluated further.

Does weight loss improve semen quality and reproductive hormones? results from a cohort of severely obese men

BackgroundA high body mass index (BMI) has been associated with reduced semen quality and male subfecundity, but no studies following obese men losing weight have yet been published. We examined semen quality and reproductive hormones among morbidly obese men and studied if weight loss improved the reproductive indicators.MethodsIn this pilot cohort study, 43 men with BMI > 33 kg/m2 were followed through a 14 week residential weight loss program. The participants provided semen samples and had blood samples drawn, filled in questionnaires, and had clinical examinations before and after the intervention. Conventional semen characteristics as well as sperm DNA integrity, analysed by the sperm chromatin structure assay (SCSA) were obtained. Serum levels of testosterone, estradiol, sex hormone-binding globulin (SHBG), luteinizing hormone (LH), follicle-stimulating hormone (FSH), anti-Müllerian hormone (AMH) and inhibin B (Inh-B) were measured.ResultsParticipants were from 20 to 59 years of age (median = 32) with BMI ranging from 33 to 61 kg/m2. At baseline, after adjustment for potential confounders, BMI was inversely associated with sperm concentration (p = 0.02), total sperm count (p = 0.02), sperm morphology (p = 0.04), and motile sperm (p = 0.005) as well as testosterone (p = 0.04) and Inh-B (p = 0.04) and positively associated to estradiol (p < 0.005). The median (range) percentage weight loss after the intervention was 15% (3.5 - 25.4). Weight loss was associated with an increase in total sperm count (p = 0.02), semen volume (p = 0.04), testosterone (p = 0.02), SHBG (p = 0.03) and AMH (p = 0.02). The group with the largest weight loss had a statistically significant increase in total sperm count [193 millions (95% CI: 45; 341)] and normal sperm morphology [4% (95% CI: 1; 7)].ConclusionThis study found obesity to be associated with poor semen quality and altered reproductive hormonal profile. Weight loss may potentially lead to improvement in semen quality. Whether the improvement is a result of the reduction in body weight per se or improved lifestyles remains unknown.

Associations of in utero exposure to perfluorinated alkyl acids with human semen quality and reproductive hormones in adult men.

Background: Perfluorinated alkyl acids (PFAAs), persistent chemicals with unique water-, dirt-, and oil-repellent properties, are suspected of having endocrine-disrupting activity. The PFAA compounds perfluorooctanoic acid (PFOA) and perfluorooctane sulfonic acid (PFOS) are found globally in humans; because they readily cross the placental barrier, in utero exposure may be a cause for concern. Objectives: We investigated whether in utero exposure to PFOA and PFOS affects semen quality, testicular volume, and reproductive hormone levels. Methods: We recruited 169 male offspring (19–21 years of age) from a pregnancy cohort established in Aarhus, Denmark, in 1988–1989, corresponding to 37.6% of the eligible sons. Each man provided a semen sample and a blood sample. Semen samples were analyzed for sperm concentration, total sperm count, motility, and morphology, and blood samples were used to measure reproductive hormones. As a proxy for in utero exposure, PFOA and PFOS were measured in maternal blood samples from pregnancy week 30. Results: Multivariable linear regression analysis suggested that in utero exposure to PFOA was associated with lower adjusted sperm concentration (ptrend = 0.01) and total sperm count (ptrend = 0.001) and with higher adjusted levels of luteinizing hormone (ptrend = 0.03) and follicle-stimulating hormone (ptrend = 0.01). PFOS did not appear to be associated with any of the outcomes assessed, before or after adjustment. Conclusions: The results suggest that in utero exposure to PFOA may affect adult human male semen quality and reproductive hormone levels.

A very large proportion of young Danish women have polycystic ovaries: is a revision of the Rotterdam criteria needed?

BACKGROUND According to the Rotterdam 2003 criteria, an ovary is defined as polycystic if 12 or more follicles of 2-9 mm are present, when evaluating the ovary by ultrasonography on Days 3-5 of the menstrual cycle in women not using hormonal contraceptives. The aim of this population-based study was to estimate the prevalence of polycystic ovaries (PCO) in a representative sample of young Danish women according to the Rotterdam criteria. METHODS From a Danish pregnancy cohort established in 1988-1989, 267 (61%) young adult daughters agreed to participate in a clinical examination and 174 (40%) consented to vaginal ultrasound. Sufficient image quality in at least one ovary was obtained from 154 women. Both users and non-users of hormonal contraceptives were included and the examination was not restricted to a particular time of the menstrual cycle. RESULTS The median (range) age was 20.1 (19.5-21.0) years. The median follicle number per ovary was 14 (6-30) and 12 or more follicles were counted in 104 of the 154 women. Thus, the prevalence was estimated to 68% [95% confidence interval (CI): 60-74%]. PCO were present in 80% (95% CI: 65-89%) of non-users (n = 44) of hormonal contraceptives. Of the 104 women with PCO, 41% (95% CI: 32-51%) could be defined as having polycystic ovary syndrome. CONCLUSIONS A very large proportion of the young women had PCO according to the Rotterdam 2003 criteria. As the number of follicles is higher at a younger age, we believe the Rotterdam criteria should be revised, particularly to avoid misdiagnosis in this age group.

Are serum levels of vitamin D associated with semen quality? Results from a cross-sectional study in young healthy men

OBJECTIVE To examine the association between low serum vitamin D concentration and estimates of male reproductive function. DESIGN Cross-sectional study. SETTING University hospital. PATIENT(S) From a Danish pregnancy cohort established in 1984-1987, 347 sons were selected for a study conducted in 2005-2006. INTERVENTION(S) Semen parameters and reproductive hormones were related to vitamin D concentrations in 307 men. MAIN OUTCOME MEASURE(S) Semen characteristics and reproductive hormones. RESULT(S) A high vitamin D level was unexpectedly associated with lower crude median total sperm count and percentage of normal morphology sperm and a high level of crude median sex hormone-binding globulin and FSH. After adjustment, the associations attenuated to nonsignificant associations, except for sex hormone-binding globulin. Additionally, adjusted free androgen index was lower at higher vitamin D levels, and men with high vitamin D had 11% (95% confidence interval, 1%-20%) lower free androgen index compared with men with low vitamin D. CONCLUSION(S) These results do not indicate that low vitamin D is a risk factor for poor semen quality in a population of young healthy men, but we may not have enough men with low vitamin D levels to detect an effect. New studies should include a larger proportion of vitamin D-deficient men.

The association between circulating levels of antimüllerian hormone and follicle number, androgens, and menstrual cycle characteristics in young women

OBJECTIVE To investigate the association between serum antimüllerian hormone (AMH) and other reproductive parameters in young women. DESIGN Cross-sectional study. SETTING University hospital. PATIENT(S) Population-based cohort of 256 women: 180 were users and 76 were nonusers of hormonal contraceptives. INTERVENTION(S) None. MAIN OUTCOME MEASURE(S) Antral follicles, androgens, age at menarche, and duration and regularity of menstrual cycle. RESULT(S) AMH levels were lower among users of hormonal contraceptives compared to nonusers. Among nonusers, women with AMH levels in the upper tertile had 55% (95% confidence interval [CI]: 22%-99%) higher levels of total T and 8% (95% CI = 2%-15%) longer menstrual cycles than women with AMH levels in the lower tertile. An increase of 1 ng/mL in AMH was associated with 45% (95% CI = 6%-97%) higher prevalence of irregular menstrual cycles. These associations were not seen among users of hormonal contraceptives. A strong relationship between AMH and follicle number was found in both users and nonusers. CONCLUSION(S) AMH measurements were found to be applicable in evaluation of the reproductive function of young women. However, there may be differences in the way that serum AMH levels can be interpreted depending on whether the woman uses hormonal contraceptives or not.

Caesarean delivery and risk of developing asthma in the offspring

Aim: To evaluate the association between caesarean section and risk of developing asthma.

Semen quality and reproductive hormones according to birthweight and body mass index in childhood and adult life: two decades of follow-up

OBJECTIVE To investigate the association between childhood body mass index (BMI), birth weight, and adulthood BMI, and adult semen quality and level of reproductive hormones. DESIGN Follow-up study. SETTING From a pregnancy cohort established in 1984-1987. PATIENT(S) 347 out of 5,109 sons were selected for a study conducted 2005 to 2006. INTERVENTION(S) Semen and blood samples were related to information on BMI in boys (5-8 years), birth weight, and adult BMI. MAIN OUTCOME MEASURE(S) Semen characteristics and reproductive hormones. RESULT(S) Neither childhood BMI, birth weight, nor adulthood BMI were significantly associated with semen quality. Men with the 33% highest childhood BMI had 15% lower sex hormone binding globulin, 8% lower testosterone, and 16% lower FSH than men with the 33% lowest childhood BMI. Men with high adulthood BMI had 14% lower testosterone, 9% lower inhibin B, 31% lower sex hormone binding globulin, and 20% higher estradiol than men with low adulthood BMI. CONCLUSION(S) The results do not indicate an effect of childhood BMI, birth weight, or adult BMI on semen quality, but the exposure contrast in our study was limited. The hormonal status was affected by adult BMI.

Maternal cigarette smoking during pregnancy and reproductive health in children: a review of epidemiological studies

Maternal cigarette smoking may affect the intrauterine hormonal environment during pregnancy and this early fetal exposure may have detrimental effects on the future trajectory of reproductive health. In this review, we discuss the epidemiological literature on the association between prenatal exposure to maternal cigarette smoking and several aspects of reproductive health. The literature points towards an increased risk of the urogenital malformation cryptorchidism, but a potential protective effect on the risk of hypospadias in sons following prenatal cigarette smoking exposure. Studies on sexual maturation find a tendency towards accelerated pubertal development in exposed boys and girls. In adult life, prenatally exposed men have impaired semen quality compared with unexposed individuals, but an influence on fecundability, that is, the biological ability to reproduce, is less evident. We found no evidence to support an association between prenatal cigarette smoking exposure and testicular cancer. Among adult daughters, research is sparse and inconsistent, but exposure to cigarette smoking in utero may decrease fecundability. In conclusion, prenatal exposure to cigarette smoking may cause some long-term adverse effects on the reproductive health.

Semen quality according to prenatal coffee and present caffeine exposure: two decades of follow-up of a pregnancy cohort

BACKGROUND A few studies have investigated the association between male caffeine consumption in adult life and semen quality with conflicting results, but so far no studies have explored the effect of prenatal coffee exposure. We studied the association between prenatal coffee and current caffeine exposure and semen quality and levels of reproductive hormones. METHODS From a Danish pregnancy cohort established in 1984-1987, 347 sons out of 5109 were selected for a follow-up study conducted 2005-2006. Semen and blood samples were analyzed for conventional semen characteristics and reproductive hormones and were related to information on maternal coffee consumption during pregnancy and present caffeine consumption. Data were available for 343 men. RESULTS There was a tendency toward decreasing crude median semen volume (P = 0.06) and adjusted mean testosterone (P = 0.06) and inhibin B (P = 0.09) concentrations with increasing maternal coffee consumption during pregnancy. Sons of mothers drinking 4-7 cups/day had lower testosterone levels than sons of mothers drinking 0-3 cups/day (P = 0.04). Current male caffeine intake was associated with increasing testosterone levels (P = 0.007). Men with a high caffeine intake had approximately 14% higher concentration of testosterone than those with a low caffeine intake (P = 0.008). CONCLUSIONS The results observed in this study are only tentative, but they do not exclude a small to moderate effect of prenatal coffee exposure on semen volume and levels of reproductive hormones. Present adult caffeine intake did not show any clear associations with semen quality, but high caffeine intake was associated with a higher testosterone concentration.