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BACKGROUND: The combination of etonogestrel implants with injectable testosterone decanoate was investigated as a potential male contraceptive. METHODS: One hundred and thirty subjects were randomly assigned to three treatment groups, all receiving two etonogestrel rods (204 mg etonogestrel) and 400 mg testosterone decanoate either every 4 weeks (group I, n = 42), or every 6 weeks (group II, n = 51) or 600 mg testosterone decanoate every 6 weeks (group III, n = 37) for a treatment period of 48 weeks. RESULTS: One hundred and ten men completed 48 weeks of treatment. Sperm concentrations of <1 x 10(6)/ml were achieved in 90% (group I), 82% (group II) and 89% (group III) of subjects by week 24. Suppression was slower in group II, which also demonstrated more frequent escape from gonadotrophin suppression than groups I and III. Peak testosterone concentrations remained in the normal range throughout in all groups. Mean trough testosterone concentrations were initially subphysiological but increased into the normal range during treatment. Mean haemoglobin levels increased in group I, and a non-significant increase in weight and decline in high-density lipoprotein cholesterol was observed in all groups. Fourteen subjects discontinued treatment due to adverse events. CONCLUSIONS: Subcutaneous etonogestrel implants in combination with injectable testosterone decanoate resulted in profound suppression of spermatogenesis that could be maintained for up to 1 year. Efficacy of suppression was less in group II, probably due to inadequate testosterone dosage. This combination has potential as a long-acting male hormonal contraceptive.

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OBJECTIVES: To assess the reliability of a classification scheme and interview questions to be used for retrospective expose assessment in a study on reproductive disorders among hairdressers. Based on the presence of an air cleaning device (yes or no) and setting waves (yes or no), this scheme divides hairdressers into groups with potentially high and low exposure to solvents. The reliability of this and other schemes was assessed. Also; the reliability of self reports on other job characteristics was evaluated. METHODS: The monitored hairdressers were interviewed one or two years after measurements were performed. Based on the interview information, hairdressers were classified into exposure groups according to the original and other classification schemes. Measured ethanol concentrations were compared between the classified exposure groups. Furthermore, the interview answers were compared with the registered information one to two years ago. RESULTS: Using self reports, the original scheme resulted in mean ethanol concentrations (used as indicator variable) of 11.8 and 7.4 mg/m3 for the high and low exposure groups, respectively. The resolution was slightly less than for the original classification based on observations (15.0 and 7.1 mg/m3). Surprisingly, the self reported presence of any ventilation device resulted in more contrast in mean exposure concentration between the groups (17.4 and 7.5 mg/m3, respectively). Hairdressers reported validly on salon characteristics such as the type of salon, the number of hairdressers that worked in the salon, and the presence of ventilation devices, but could not make a distinction between different kinds of ventilation devices. The numbers of customers and tasks performed were largely overreported, but most variables correlated significantly with the information registered during the measurements. CONCLUSION: The self reported presence of any ventilation device is most predictive for the level of exposure to ethanol in the hairdressing salon. Questionnaire data on work characteristics should be treated with caution.

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To evaluate whether hairdressers have an increased risk of reproductive disorders, we conducted a historical cohort study in the Netherlands. Because exposure to reproduction toxic agents in hair salons may have changed over time, we studied two specific periods: conceptions in 1986-1988 and in 1991-1993. We ascertained 9,000 hairdressers and, as a comparison group, 9,000 clothing salesclerks from their respective trade associations. All were of reproductive age in the defined study periods. Frequency matching on 5-year age groups ensured comparability with regard to age. All women were approached by mail to complete a short, self-administered questionnaire on reproductive history, including questions on time-to-pregnancy, spontaneous abortion, livebirths, and congenital malformations. In the analyses, we used random effect models to account for correlated outcomes (multiple pregnancies per woman). The results show that hairdressers who conceived in 1986-1988 had an increased risk of prolonged time-to-pregnancy of more than 12 months [odds ratio (OR) = 1.5; 95% confidence interval (CI) = 0.8-1.6], spontaneous abortion (OR = 1.6; 95% CI = 1.0-2.4), and a low-birthweight infant (OR = 1.5; 95% CI = 0.7-3.1). In both periods, more major malformations occurred among children of hairdressers, but numbers were small. These results indicate an increase in reproductive risks for hairdressers in earlier years that now seems to be disappearing.

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The hypothesis that intrauterine exposure to hairdressers' chemicals adversely affects neurodevelopment of the offspring was investigated. Neurodevelopmental characteristics were analysed using a historical cohort study of reproductive disorders among hairdressers in The Netherlands. Because exposure in hair salons to agents toxic to reproductive processes might have changed over time, two specific study periods were examined: from 1986 to 1988 and from 1991 to 1993. Nine thousand hairdressers and 9000 clothing sales clerks (referent group) who were in the reproductive age in the defined study periods were selected by the trade association for service jobs. Frequency matching assured comparability with regard to age. All women were invited by mail to complete a short self-administered questionnaire on their reproductive history, including questions on the ages of their child at the times of the first words, first sentences, and first steps, and the occurrence of seizures during fever. The results showed that in 1986 to 1988 more children of hairdressers started speaking their first words after 15 months and their first sentences after 24 months. For 1991 to 1993 no increased risks of these outcomes were found. Seizures during fever had occurred more often among children of hairdressers in 1986 to 1988, and in 1991 to 1993, especially when women had been working until maternity leave. Although the quality of the data in this explorative study requires careful interpretation, the consistent results seem to indicate adverse effects on neurodevelopment among offspring of hairdressers in the earlier years (1986 to 1988). In the later years the effect seemed to be disappearing. However, these findings should be confirmed in more detailed studies.

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The evidence for reproductive disorders due to chemical exposure among hairdressers was evaluated. To this end, a literature study was conducted on Medline for the years 1985-1993. Reproductive disorders in humans were described for solvents such as ethanol and dichloromethane found mainly in hair sprays. Reproductive effects of several dye formulations, ethylene glycol ethers, nitrosamines, formaldehyde, hexachlorophene, and phthalic esters cannot be excluded, but few human data on low concentrations of these agents were available. Associations with menstrual disorders and spontaneous abortions were found in epidemiologic studies focused on hairdressers. Other studies showed inconsistent results, probably due to methodological shortcomings (misclassification of exposure, small sample sizes). It is concluded that there is little evidence for reproductive disorders among hairdressers to date. Limited availability of human data and unknown effects of chemical mixtures call for future research focused on human reproductive risks among hairdressers with emphasis on exposure assessment in the hairdressing salon.

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Menstrual characteristics in a population of 23,227 women who participated in a breast cancer screening programme were considered with respect to month of birth. High and low risk months of birth were defined according to the seasonal preovulatory overripeness ovopathy (SPrOO) hypothesis. Positive associations were found in 11 out of the 14 relations studied. The results were significant for early menarche (< or = 11 years), long menstrual cycles (> or = 5 weeks), menorrhagia (> or = 7 days and profuse blood loss), and early (< or = 40 years) or late (> or = 56 years) menopause. The results not only confirm the birth excess of these women in specific months, as has been found by others. They apparently agree with the SPrOO hypothesis and with a transgenerational concept of familial subfecundability along matrilineal lines and hence, familial clustering of pathological progeny, independent of Mendelian rules.

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By using the Nijmegen data base on breast cancer we attempted to determine whether a relationship exists between menstrual pattern and month of birth and if so, if its agreed with the hypothesis of Seasonal Preovulatory Overripening Ovopathy (SPrOO). On the basis of the birth curve of women who participated in the Nijmegen breast cancer screening programme (1975) risk months for SPrOO and reference months were defined. We found that more women born in a risk month had an early menarche (< or = 11 years), a long menstrual cycle (> or = 5 weeks; QI: 20-25 kg/m2), menorrhagia, and an early (35-40 years) or late (> or = 56 years) menopause age. This relationship was in line with the predictions according to the SPrOO hypothesis. In all, a positive (but not always significant) relationship appeared to exist in 12 of the 15 associations studied. We conclude that there is a relationship between menstrual pattern and month of birth, which can be explained by the SPrOO hypothesis.

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