Biomedical subjects
J L Boldsen
Publications and source records attributed to J L Boldsen.
[Continuously diminishing menarcheal age in Denmark].
INTRODUCTION: The aim was to follow the development of the parameters of the distribution of age at menarche in Danish women in recent decades. MATERIAL AND METHODS: The study is based on retrospective data from six different samples with a total of 42,784 women, born in the period 1923-1973. RESULTS: We report a renewed decline in the mean menarcheal age in a large Danish sample after a period with a halt in the trend towards an earlier age at menarche in many North European countries. We find a continuously declining mean menarcheal age in Denmark in women born in the years 1964-1973. In a sample of textile workers born in the years 1939-1968 (n = 12,605) we find a higher mean menarcheal age of one year. DISCUSSION: The results indicate that menarcheal age is still delayed in certain groups in Denmark. It can therefore be expected that the menarcheal age will fall even more in the future.
Epidemiological approach to the paleopathological diagnosis of leprosy.
In paleopathology it is usually assumed that modern diagnostic criteria can be applied to infectious diseases in the past. However, as both the human species and populations of pathogenic microorganisms undergo evolutionary changes, this assumption is not always well-founded. To get valid estimates of the frequency (the point prevalence at death) of leprosy in skeletal samples, sensitivity, specificity, and sample frequency must be estimated simultaneously. It is shown that more than three symptoms must be evaluated in at least three samples in order to reach estimates with well-described properties. The method is applied to three skeletal samples from Medieval Denmark; the samples were scored for the presence of seven osteological conditions indicating leprosy. For the osteological conditions, sensitivity varied from 0.36-0.80, and specificity from 0.58-0.98. The frequency of leprosy in the three samples was: Odense (a lepers' institution), 0.98, 95% CI 0.64-1.00; Malmö (urban cemetery), 0.02, 95% CI 0.00-0.07; and Tirup (rural cemetery), 0.36, 95% CI 0.23-0.46. It is concluded that it is indeed possible to estimate disease frequencies without reference to modern standards, and that leprosy occurred with widely differing frequencies in different segments of the Medieval population in southern Scandinavia.
Low bone mineral density in the femoral neck of medieval women: a result of multiparity?
An archaeological investigation of a medieval cemetery gave us the opportunity to investigate 49 Danish skeletons dating from 1000 to 1250 A.D. and to compare them with 298 contemporary Danes (aged 19-79 years) and assess the millennial trend in bone mineral density (BMD) in populations considered genetically closely related. BMD and bone mineral apparent density (BMAD) of the femoral neck were measured by dual-energy X-ray absorptiometry (DEXA) and transformed into z scores. BMD(zscore) was significantly lower in medieval women (-0.54 +/- 0.25, p = 0.04), whereas BMD(zscore) in medieval men was significantly higher (0.55 +/- 0.22, p = 0.02). In medieval women, BMD(zscore) tended to increase with age (r = 0.42, p = 0.07), whereas no change was seen in men (r = 0.19, not significant [n.s.]). Also, BMAD(zscore) was significantly elevated in medieval men (1.00 +/- 0.28, p < 0.01), but in medieval women no difference was found (-0.28 +/- 0.21, n.s.). However, the correlation between BMAD(zscore) and age was significant in the medieval women where it increased with advancing age (r = 0.49, p = 0.03). In conclusion, medieval women had lower BMD when compared with contemporary women, but this relationship was reversed in women who survived to older ages. In contrast, medieval men had significantly higher BMD as compared with contemporary men at all ages. The observed lower BMD in medieval women can be explained by the well-known selective mortality among the younger women. A high birth rate and prolonged periods of lactation are the main reasons for the observed increased mortality, and therefore can also very likely explain the associated low BMD. The increase in the incidence of osteoporosis in modern elderly women could possibly, or partially, be explained by the survival of women who would have died prematurely had they lived in earlier centuries.
[Suicide among patients with apoplexy. An epidemiological study].
The purpose of this study was, on the basis of a cohort of patients with a discharge diagnosis of stroke (ICD8 code: 430-438) diagnosed in the period 1.4.1973-31.12.1989 in a representatively selected area of Denmark (County of Funen), to estimate whether or not the risk of suicide in stroke patients was increased compared to the background population, i.e. the total population of the County of Funen. The patients were followed for causes of death until end of 1989. Standard Mortality Ratios for suicide standardized for age and sex in male and female stroke patients were calculated. A total of 37,869 stroke patients were included in the study, 140 committed suicide in the study period (80 females and 60 males). Standard Mortality Ratio for suicide was significantly increased for all stroke patients. For women below 49 years and from 50-59 years Standard Mortality Ratios were 1376 and 1378 respectively. For men below 49 years and from 50-59 years Standard Mortality Ratios were 656 and 580 respectively. The suicides did not occur at any specific time-point after the stroke. The results of this study emphasize the need, concurrently with improvements in prevention and treatment of stroke, to improve the care of patients suffering from the impairment of a stroke. This is a continuous process, and studies are needed in order to decide how this is best done.
[Discrepancies between diagnosed asthma, asthma-like symptoms and a test for abnormal lung function].
For the diagnosis of asthma, it is neither clear to which degree various tests and symptoms identify the same subjects nor how these characteristics are best combined. We assessed the interrelationship between physician-diagnosed asthma, asthma-like symptoms and abnormal airway function in a population based sample of 495 12-15 year old schoolchildren. Participants filled in a questionnaire and underwent baseline spirometry (FEV1%), provocation with treadmill exercise (EXE) and with inhaled methacholine (PD15), and monitoring of peak expiratory flow (PEF) twice daily for two weeks. Most symptomatic subjects with any test positive were identified by PD15 alone (75%) or in combination with PEF monitoring (89%). Although interest agreement was weak (kappa < 0.40 for all pairs), significant associations were found between PD15 and EXE, between PEF and EXE and between FEV1% and PD15. However, PEF variability and methacholine responsiveness seem to identify different varieties of airway pathophysiology, and the combined use of the two tests may be helpful as an epidemiological screening tool for asthma.
[Age at menarche among schoolgirls in Odense. Is age at menarche still decreasing in Denmark?].
The average age at the menarche has decreased from the 1850s to the 1950s. It is controversial whether there has been a continued decrease since the 1950s. The object of this investigation is to illustrate whether this trend has continued into the 1980s. This study is based on the ages at the menarche as recalled by 908 girls aged 14-16 years in 40 schools in Odense. The information was obtained during intervals of differing lengths and consequently, the parameters of the distribution of the age at the menarche were estimated in a randomly grouped normal distribution. The average age at the menarche was found to be the same throughout the municipality (13.27 years; 95% confidence limit 13.20-13.35). The variations were found to be significantly differentiated by the type of school district. The variations were low in the suburbs and in the surrounding rural districts, higher in the inner city areas and highest among girls attending private schools. Compared with the results from other recent Danish studies, these findings suggest a halt in the decline of the average age at the menarche, which may be temporary.
Season of birth and recalled age at menarche.
All 8th-form schoolgirls from the municipality of Odense in Denmark were asked at what age they reached menarche, and 886 girls (97.6%) gave this information. There is no evidence for seasonality in the time of birth but for far more girls than expected menarche occurred during winter or summer and fewer than expected during spring and autumn. This pattern appears primarily in girls living in the suburbs and was not seen in those living in central Odense. The seasonality appears to be brought about by differences in mean age at menarche according to time of the year at birth.
Geographical distribution of some Danish surnames: reflections of social and natural selection.
Geographical differences in the frequencies of eight common surnames in Jutland (Denmark) are analysed using data from telephone directories of 121 exchanges. All the names showed a significant geographical surplus variance, which was divided into trend and patchiness components reflecting the history of the names. The surplus variance of surnames with restricted areas of origin was dominated by a large trend component; for surnames with an originally more even distribution, the patchiness component was dominant. The patterns of distribution were affected by processes which modelled natural selection with linkage disequilibrium. The combined patchiness within the clusters of exchanges gave information about patterns of local migration and level of social integration in the communities. Areas situated in boundary regions show high levels of patchiness.
Waiting time to pregnancy and pregnancy outcome among Danish workers in the textile, clothing, and footwear industries.
The relationship between time from planned to achieved pregnancy and pregnancy outcome has been studied in a group of 18,658 workers in the textile, clothing and footwear industries. Information on pregnancy outcome and delay in conception in the period 1979-84 was collected by self administered questionnaires in 1985. The response rate was 70.3%. During the study period there had been 5,171 live births and 708 spontaneous abortions. Information on delay in conception was collected in broad categories. The data were analysed by means of a newly developed statistical parametric model in order to collect all possible information from the highly grouped data. Median waiting time before a pregnancy which ended in spontaneous abortion was 1.68 times longer than median waiting time before a pregnancy leading to a live birth. There seems to be a correlation between the length of the waiting time and abortion.
Aspects of comfort and safety of condom. A study of two thousand intercourses among volunteer couples.
In nearly 2,000 intercourses 14 different types of condoms were tested by 80 heterosexual and seven homosexual volunteer couples. The test couples were generally quite experienced in the use of condoms. It appears that the condoms rarely (1.3%) ruptured or slipped off during the actual intercourse. This means that emphasis must be put on consistency and skill in the use of condoms rather on technical improvements in the promotion of condoms as a means of preventing the spread of sexually transmitted infections like HIV. Lubricated condoms and condoms that were not too small were preferred by both users and their partners. Other condom properties were significant but of minor concern for the participants of the study.
Childhood conditions and adult height.
Self-reported height and childhood conditions among 1711 Danish male general workers born between 1923 and 1940 were analysed. No significant associations were found between adult height and father's occupation, growing up with both parents, paternal unemployment, sickness among the parents, parents receiving disability pension, economical problems in childhood, area of residence in childhood, and years at school. The study therefore provides no support for the hypothesis that poor childhood conditions are the cause of low adult height in this socially very homogeneous sample.
Time to pregnancy--a model and its application.
Biological fertility is poorly measured by the number of children born in industrially advanced societies. The time elapsing from when a couple decides to have a child to clinically recognizable pregnancy is a useful alternative. Time to pregnancy can be collected in broad categories in large samples. A model for condensing important information from such data is presented, which fits several large samples of reported waiting times. It is shown that multiparous women conceive more quickly than primiparous women.
Evidence for maternal inheritance of female height in a British national sample.
Analyses of the height variation in a large contemporary British sample found evidence for maternal inheritance of female height, because the mother-daughter correlation coefficient was significantly higher than the father-daughter value. Further evidence for a maternal effect came from the comparison of the daughter's stature with the difference in parental heights. The maternal effect was estimated to be 1%.
Distribution of age at menopause in two Danish samples.
We analyzed the distribution of reported age at natural menopause in two random samples of Danish women (n = 176 and n = 150) to determine the shape of the distribution and to disclose any possible trends in the distribution parameters. It was necessary to correct the frequencies of the reported ages for the effect of differing ages at reporting. The corrected distribution of age at menopause differs from the normal distribution in the same way in both samples. Both distributions could be described by a mixture of two normal distributions. It appears that most of the parameters of the normal distribution mixtures remain unchanged over a 50-year time lag. The position of the distribution, that is, the mean age at menopause, however, increases slightly but significantly.
Relationship between biological and social aspects of sexual maturity among young Danes.
Representative samples of 286 young Danish women and 336 young men aged 16-20 years were interviewed in 1984-1985 about menarcheal age and age at 1st sexual intercourse. The medium age at menarche was 13.13 years. Altogether 212 (74%) of females and 225 (70%) of males were sexually experienced. Among females the medium age at sexual debut is related to that at menarche in the 4 cohorts investigated where it was possible to estimate both variables. Consequently, the behavioral aspects of sexual maturity among females is heavily influenced by this purely biological index of maturation. Although the median age at 1st sexual intercourse could only be estimated in 3 of the male cohorts an indication of association between the median ages at sexual debut is clear, and they seem to follow the median age of menarche closely. The interrelationship between this biological factor (menarche) and a social event (1st sexual intercourse) indicates a causality in sexual development of young contemporary Danes.
Development indices of maturity in females.
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An analysis of the geographical distribution of selected British surnames.
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