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Lone Storgaard

Publications and source records attributed to Lone Storgaard.

11 recordsLinked to original sources
PubMed2006

Genetic and environmental correlates of semen quality: a twin study.

BACKGROUND: The influences of environmental factors on the male reproductive system have been much debated over the last 3 decades. We studied the impact of genes and environment on semen quality, sex hormone levels, and sperm chromatin stability by using a twin design. METHODS: The study population consisted of monozygotic and dizygotic twins from the population-based Danish Twin Registry and a random selection of pairs of singleton brothers from the Danish Civil Registration System. All men were 20 to 45 years of age. The study population comprised 100 monozygotic twin brothers (50 pairs), 102 dizygotic twins (51 pairs), and 102 single-born brothers (51 pairs). A semen sample and blood sample were collected from all participants. RESULTS: Heritability was estimated to account for 20% (95% confidence interval = 0% to 68%) of the variation in sperm density. A higher heritability was found for the hormones reflecting Sertoli cell function (inhibin B, 76% [36% to 84%] and follicle-stimulating hormone, 81% [40% to 88%]) and for percent morphologic normal cells (41% [0% to 60%] and sperm chromatin parameters (mean alphaT, 68% [34% to 81%] and COMP alphaT, 72% [25% to 82%], respectively). CONCLUSION: Our study indicates a substantial hereditary component in plasma levels of hormones reflecting Sertoli cell function and in sperm cell chromatin stability and morphology. The environmental contribution (including the prenatal environment) appeared to be largest for sperm count.

Adult↗
PubMed2005

Male reproductive disorders in humans and prenatal indicators of estrogen exposure. A review of published epidemiological studies.

Male reproductive disorders in humans and prenatal indicators of estrogen exposure. A review of published epidemiological studies. Reports of an increase in male reproductive disorders in several countries led to the hypothesis that estrogens during fetal life may cause reduced sperm counts, cryptorchidism, hypospadias and testicular cancer. So far the hypothesis is based on animal studies and reports from the wild life. We systematically searched the epidemiological literature for evidence linking indicators of prenatal serum levels of maternal estrogens with sperm density, hypospadias, cryptorchidism and testicular cancer in humans. Indicators of fetal estrogen exposure included direct measurements, recorded intake of hormones (diethylstilbestrol (DES), oral contraceptives (OCs) and estrogens), pregnancy conditions with known deviant estrogen level as for instance twin pregnancies and some environmental exposures. Among 425 papers we reviewed 81 publications with appropriate information. With the possible exception of testicular cancer there is no strong epidemiological evidence to indicate that prenatal exposure to estrogen are linked to disturbed development of the male reproductive organs.

Cryptorchidism↗
PubMed2003

[Is change of general practitioners more frequent among patients diagnosed with cancer or other serious diseases?].

INTRODUCTION: Change of GP may imply that the patient is dissatisfied with the health service provided. The aim of this study was to investigate whether newly diagnosed cancer patients change their GP more often than other patient groups and the background population. MATERIAL AND METHODS: The investigation was conducted using data on inhabitants from the counties of Aarhus, Vejle and South Jutland. We included 900 Group 1 insured patients, aged 18-75 years, distributed into three groups: 1) frequent cancers, 2) rare cancers and 3) benign, but chronic or severe new diseases. The diagnoses included occurred for the first time at the time of inclusion. Three hundred controls were randomly selected from the regional health care registry in Aarhus. The study period was from March 1 to August 30 1994. A change of GP was defined as a change not caused by the patient's change of residence or the GP's change of practice registration number due to expansion, takeover or split up of practice. RESULTS: In the three disease groups, 28 cases of change of GP were registered with a frequency of 5% (frequent cancers), 2.7% (rare cancers) and 1.7% (benign, but chronic or severe new diseases). The frequency in the background population was 2.7%. None of the differences were statistically significant. DISCUSSION: During the first year following a cancer or chronic disease diagnosis, change of GP is rare, particularly among patients with rare cancers. We reject the hypothesis that change of GP is frequent among newly diagnosed cancer patients.

Adolescent↗
PubMed2003

Does smoking during pregnancy affect sons' sperm counts?

BACKGROUND: There has been an apparent decline in sperm density during the last 5 decades in Denmark, a country in which women have among the highest rates of smoking in Europe. We examined semen quality and sex hormones in men in relation to their mothers' tobacco smoking during pregnancy. METHODS: Male participants were selected from the population-based Danish Twin Registry and the Danish Civil Registration System as part of a study on hereditary and environmental determinants of semen quality. From November 1999 to May 2000 we collected one fresh semen and blood sample from each of 316 men. Data on prenatal tobacco exposure were obtained for 265 of these men from a questionnaire filled in by their mothers. RESULTS: Adjusting for age, current smoking status and other factors, sperm density was 48% lower(95% confidence interval = -69% to -11) among sons of mothers who smoked more than 10 cigarettes per day during pregnancy. Total sperm counts and levels of inhibin-B were also reduced among this group, whereas follicular stimulating hormone levels were somewhat higher (16% increase; 95% confidence interval = -13% to 54%). These effects were not seen in the lower smoking category (1-10 cigarettes per day). CONCLUSIONS: High levels of smoking (> 10 cigarettes per day) during pregnancy may be a partial explanation for the apparent secular decline and the geographic differences in sperm counts.

Adult↗
PubMed2002

How work-place conditions, environmental toxicants and lifestyle affect male reproductive function.

Major temporal and geographical shifts in male reproductive function is presently an issue worldwide. The hormonal disruption hypothesis has achieved considerable attention but epidemiological evidence in support of the theory is lacking. Several occupational hazards to male reproductive function are known but exposure prevalences are hardly sufficient to play a role for reduced sperm count in the general male population. Sedentary work may be an exception. Perhaps prolonged time in the sedentary position exhausts the testicular heat regulation. But so far studies addressing implications of the heat hypothesis in the general population are few. Neither change of sexual behaviour nor reduced period of sexual continence seems to be a likely explanation. Tobacco smoking and consumption of caffeine and alcoholic beverages in adulthood have a rather marginal impact on spermatogenesis and can hardly explain major shifts or regional differences in male reproductive health. However, prenatal effects following smoking during pregnancy might play a role because we have witnessed a smoking epidemic among fertile women in some countries during the second half of the twentieth century. Moreover, if genetic factors play more than a marginal role for testicular function and sperm count, pregnancy planning resulting in reduced family size during the past 100 years could possibly explain a decline in semen quality because the most fertile part of the population reproduce less while the subfertile probably continue to get a limited number of children.

Body Temperature Regulation↗
PubMed2002

Correlation of scrotal temperature in twins.

BACKGROUND: Scrotal temperature and semen quality have been found to be inversely correlated in several studies, and variation in scrotal temperature may contribute to the well known variation in semen quality. The reason for the variation in scrotal temperature is not well understood although determinants could be of a genetic nature. METHODS: We monitored scrotal skin temperature for 24 h in a group of monozygotic and dizygotic twins and single-born brothers (n = 48 males). A thermistor was attached to the underwear and the temperature of the scrotal skin was recorded every 5 min using a small portable data logger. RESULTS: A correlation in median scrotal temperature was found among monozygotic twins (r = 0.64, P = 0.01), but not in dizygotic twins and single-born brothers (r = 0.17, NS). Similar results were found for other percentiles of temperature. CONCLUSIONS: The results suggest a genetic component to the variation in scrotal temperature. An hereditary element in male fecundity may be expressed through scrotal temperature, which constitutes a mechanism independent of those responsible for the development of the sperm producing epithelium.

Adult↗
PubMedDate not supplied

Impact of diurnal scrotal temperature on semen quality.

A high scrotal temperature is a common finding in infertile patients and experimental studies indicate that specific types of heat exposure reduce semen quality. More and more men have a sedentary work position, which increases scrotal temperature. Semen and blood samples from 99 healthy men were analysed in relation to scrotal skin temperature obtained by a 24-h continuous monitoring protocol. Information on sedentary position at work and during spare time was collected by questionnaires. A negative correlation was found between high scrotal temperature and sperm output. Sperm concentration decreased 40% per 1 degrees C increment of median daytime scrotal temperature (95% CI: 8-71%). Similar results were found for total sperm count, FSH, and inhibin B. Motility, morphology, pH, and testosterone were not significantly associated with temperature. Only weak and inconsistent associations were found between sedentary position and semen quality. We conclude that scrotal temperature and semen quality are closely associated. Sedentary work position encountered in ordinary jobs, although a strong determinant of scrotal temperature, does not seem to have any effect on semen quality.

Adult↗
PubMedDate not supplied

The relation between daily activities and scrotal temperature.

Normal sperm production depends on a testicular temperature below body temperature, but the thermogenic effects of daily life activities are not well known. We described the association between scrotal temperature and daily activities in 101 males using a non-invasive method for measuring scrotal temperature. A thermistor was attached to the underwear and the temperature of the scrotal skin was logged by a portable device every 5 min for 24h. Participants reported sedentary position and activities at work and during spare time in a questionnaire. Scrotal temperature was strongly correlated with sedentary work position with a dose-effect association (<1 h sedentary: 33.1 degrees C, >6 h sedentary: 34.7 degrees C, median values). The variation in sedentary work accounted for 31.5% of the variation in median temperature during the entire 24h. Sedentary position during spare time did not correlate with scrotal temperature. Median temperature at night was 1.2 degrees C higher than during the daytime. No effect was found for size or reported tightness of the underwear. In a model experiment, the deviance between testicular and scrotal temperature was estimated as maximally 0.1-0.6 degrees C, depending on the type of activity. Measuring scrotal temperature provides a valid estimate of testicular temperature and is feasible in large cohorts. We conclude that work position is an important determinant of testicular temperature.

Activities of Daily Living↗