Menarche,pregnancy, birth spacing and menopause among the Agta women foragers of Cagayan Province,Luzon, the Philippines

The reproductive histories of 74 post-menarcheal Agta Negrito women, tropical foragers of Cagayan province, north-eastern Luzon, the Philippines are described and analysed in comparison with data collected by Howell on Dobe! Kung hunter-gatherers. Among the Agta, mean age at menarche is 17, mean age at first live birth is 20·14 years, mean completed parity is 6·53 and mean age at menopause is 44. Average height is 141·24cm and average weight 36·72 kg. No time trends were detected in age at menarche and age at first live birth among the Agta. Average spacing between live births where an infant survives until the birth of the next sibling was 2·85 years. Compared to the Dobe !Kung, Agta women have later menarche, but shorter birth spacing and a longer active childbearing span.     

Physiological maturation,reproductive patterns,and female fecundability in a traditional Moroccan population (Amizmiz,Marrakech)

The interaction between age at menarche, adolescent motherhood, and subfecundity were evaluated in 496 Moroccan women 25–54 years of age from the province of Marrakech. Since this population is characterized by later sexual maturation and early marriage, significantly increased subfecundity, measured by the waiting time to first live birth and the incidence of fetal loss, was expected. Menstrual age was defined as the difference between age at marriage and age at menarche. Social access to reproduction was conditioned by age at menarche: early maturers married at a younger age, while late maturers had a significantly shorter menstrual age despite the fact that married at a significantly older age. Although there was a tendency for late maturers to have longer waiting times and more fetal loss, there were no significant differences for either variable according to menarcheal age. Women with a shorter menstrual age became pregnant within the first year after marriage significantly less frequently than women with a greater menstrual age, but did not experience a greater occurrence of fetal loss during their reproductive life. The results indirectly support the hypothesis that the regularity of ovarian function is similar among populations independent of the timing of menarche. © 1993 Wiley-Liss, Inc.     

Weight status of adult !Kung San and Kavango people from northern Namibia

An anthropometric assessment was conducted at 238 !Kung San hunter-gatherers aged between 18 and 65 years (mean = 30.8 years), 156 Kavango horticultural pastoralists aged between 18 and 61 years (mean = 29.2 years) and for 87 urbanized kavango people aged between 18 and 61 years (mean = 29.3 years) living as wage earning employees in northern Namibia. Weight status was estimated by using body mass index categories according to the recommendations of the WHO. As is typical for human populations, men were taller and heavier than women within the same ethnic groups. An interethnic comparison showed that both !Kung San women and men were lighter than Kavango women and men. The mean BMI of !Kung San women was 19.1 and of !Kung San men 19.4 kg/m². Kavango people exhibited higher average BMI values, 19.4 for women, 20.3 kg/m² for men. With the exception of the male urban Kavango people a high percentage (more than 30%) of the subjects were thin and underweight, as shown by a BMI of < 18.5 kg/m². This was especially true of the !Kung San of both sexes and the rural Kavango men. Nearly 25% of !Kung San women met the criterion of weight depletion (BMI < 17.0). The cultural transition from nomadic hunter gatherer subsistence to a more sedentary life style over the last 20 years can be interpreted as an environmental stress which affected male as well as female nutritional status. The hard economic situation of the rural Kavango people may also be a stress factor which negatively influenced their nutritional status, especially of the men. The significantly better nutritional status of the urban Kavango men may be the result of the opportunities for work as wage carners or as soldiers.     

Changes of recollected menarcheal age and month among women in Tokyo over a period of 90 years

Data on the recollected age at menarche of 47,881 women born between 1881 and 1970 were examined. The mean menarcheal age had changed from 15.1 years in those born up to 1900 to 12.5 years in those born during the 1960s. The age at menarche differed according to the month of birth, and the pattern of average age distribution by month of birth was not the same when the year of birth was different. Among women born before 1955 the menarcheal age was earlier in those born in the summer. However, among women born after 1955, menarche occurred later when they were born in the summer. The monthly distribution of menarche had also changed during this 90-year period. Two peaks in April and August were prominent among those born up to 1960. A third peak in January became also apparent in those born after 1960.     

Secular trend in age at menarche for women born between 1920 and 1979 in Rio de Janeiro, Brazil

PRIMARY OBJECTIVE: This article presents data on the secular trend in age at menarche for 1955 women from 16 to 76 years of age born between 1920 and 1979 and studied under the Nutrition and Health Survey conducted in the municipality of Rio de Janeiro, Brazil, in 1996. METHODS AND PROCEDURES: Age at menarche was defined by the retrospective method. Women were grouped according to decade of birth, and the trend was estimated using simple linear regression between age at menarche and year of birth for the following specific periods: 1920-1940, 1920-1960, 1960-1979 and 1920-1979. MAIN OUTCOMES AND RESULTS: Mean age at menarche decreased from 13.07 to 12.40 years when comparing the group of women born in the 1920s with the 1970s birth cohort, corresponding to a mean rate of -0.0123 years per year (p < 0.001). The downward trend was -0.0120 years per year (p > 0.05) for the 1920s, 30s and 40s, -0.0093 years per year (p < 0.05) for the period from 1920 to 1960, and -0.0224 years per year (p < 0.01) for the 1960s/70s. CONCLUSIONS: The results suggest a secular trend in age at menarche. The literature points to such environmental variables as improved living conditions and expanded access to health services. Within this context, age at menarche could be used as a marker for social development.     

Prevalence of menstrual pain in relation to the reproductive life history of women from the Mayan rural community

BACKGROUND: The prevalence of menstrual pain in Western societies is relatively high and has been shown to be related to many factors (e.g. age, menarche age, parity, menstrual cycle regularity, cigarette smoking, dietary habits). However, less data are available for traditional societies, within which there are, presumably, not as many potentially disturbing factors that could influence menstrual symptoms as in Western societies. AIM: The study seeks to determine the prevalence of dysmenorrhoea, and the factors related to menstrual pains in women with natural fertility (i.e. without hormonal forms of contraception). SUBJECTS AND METHODS: 177 non-smoking women between 18 and 45 years of age living in one Mayan village (Yaxcaba, Yucatan, Mexico) were the subjects of this study. The method of logistic regression was used with the dichotomous dependent variable being the presence or absence of menstrual pain together with such independent variables as age, age at menarche, number of pregnancies, age when giving birth to the first child, the weight at interview and BMI. RESULTS: The general prevalence of the menstrual pains was 28%. There was only one variable influencing dysmenorrhoea, namely the age at which women give birth to their first children. Those mothers who gave birth to their first child at an earlier age (at mean age of 19.4 vs 21.1 years) had a lower prevalence of dysmenorrhoea. CONCLUSION: In the studied traditional society the main factor related to menstrual pain was the age at which woman first gave birth. It is hypothesized that an earlier start to reproductive life in some way decreases the sensitivity of the uterus to prostaglandins.     

CYP gene polymorphisms and early menarche.

Early age at menarche is a risk factor for breast cancer. A previous study reported a significant positive association between the CYP3A4*1B variant allele and early puberty. We investigated whether polymorphisms of the CYP3A4, CYP17, CYP1B1, and CYP1A2 genes predict the age at onset of menarche. Five hundred eighty-three nulliparous women between ages 17 and 35, of various ethnic backgrounds, completed a questionnaire that included information about menstrual history. Samples of DNA were provided and used to genotype these women for polymorphic variants in the four genes. There was no significant difference in mean age at menarche between women who carried two variant CYP17 A2 alleles (12.5 years) and women who carried one or no variant allele (12.5 years) (P = 0.8, adjusted for ethnic group and year of birth). Similar results were found for the CYP1B1*3 variant allele and for the CYP1A2*1F variant allele. Women who carried two variant CYP3A4*1B alleles had an earlier mean age at menarche (12.0 years) than women who carried one or no variant allele (12.6 years) (P = 0.02). However, after adjusting for ethnic group and year of birth, no significant differences in mean age at menarche were found. The polymorphic variants of the CYP3A4, CYP17, CYP1B1, and CYP1A2 genes are unlikely to influence age of menarche.     

Secular trend in age at menarche for South Korean women born between 1920 and 1986: the Ansan Study

BACKGROUND: There is strong evidence of a downward secular trend in age at menarche in Europe and the USA during the last century and in Japan and China during the past few decades. However, no study on this trend in age at menarche has been reported in South Korea. AIM: To measure the trend in age at menarche in South Korea during the past few decades and the association of height with this trend. SUBJECTS AND METHODS: A total of 1061 South Korean women born between 1920 and 1986 were randomly recruited from Ansan Cohort Study samples and separate school girl samples, and subjected to this analysis. The data on age at menarche were collected by the retrospective method. Height was measured at time studied and assumed to be relatively constant since age at menarche. Women were grouped with respect to decade of birth and mean age at menarche was determined. The secular trends in annual age at menarche and in height were analysed by the 3-year moving average. RESULTS: Mean menarcheal age decreased from 16.8 to 12.7 years during the past 67 years, corresponding to -0.64 years per decade. Height increased from 149.23 to 161.75 cm during the same period, showing an inverse relationship in the change of trend between height and mean age at menarche. CONCLUSION: Our data suggest that the downward secular trend in age at menarche may reflect the secular change in physical growth in South Korean women during the past 67 years.     

Evolution of age at menarche and at onset of regular cycling in a large cohort of French women

BACKGROUND: Early exposure to ovarian hormones is considered to increase breast cancer incidence. The age at which the ovaries become functional is thus important. METHODS: We explored the evolution of age at first menstruation and at onset of regular cycling in 86 031 women participating in the E3N-EPIC cohort study, part of the European Prospective Investigation into Cancer. RESULTS: We observed an increase in mean age at menarche among women born between 1925 and 1930, followed by a steady decrease in the youngest birth cohorts. In contrast, age at onset of regular cycling increased gradually from 1925 onwards. There was thus a steady increase in the interval between age at menarche and at onset of regular cycling, mainly due to an increase in the percentage of women in whom regular cycling started at least 5 years after menarche (from 9.0% among women born in 1925-1929 to 20.8% in those born in 1945-1950). The increase in the interval between menarche and onset of regular cycling was even greater among women with a late menarche. CONCLUSIONS: This increase might be due to a change in dietary intake and/or physical exercise aimed at achieving the slim silhouette desired by the younger generations.     

Early childhood determinants of age at menarche in rural guatemala

The influence of early childhood determinants on age at menarche was investigated in a sample of Guatemalan women who participated as children in a nutrition intervention study conducted from 1969 to 1977. Age at menarche was retrospectively estimated in 1991 and 1992. Mean age at menarche was 13.7 (±1.3) years. Data on linear growth, diarrhea and respiratory illnesses, and energy intake from supplementation as well as home sources were available between birth and 7 years of age. Socioeconomic status (SES) data were collected in 1975. Four hundred and ninety-seven women who had reached menarche by 1992 were grouped into three categories of stunting based on their height-for-age z-scores (none, >−2.0; moderate, −2.0 SD to −3.0 SD; severe, <−3.0 SD relative to National Center for Health Statistics reference data) at 3 years of age. About 78% of the sample was moderately or severely stunted at 3 years of age. The group that was severely stunted in childhood reached menarche at 14.1 ± 1.4 years, significantly later than those who were moderately stunted (13.7 ± 1.2 years) or not stunted (13.5 ± 1.3 years). Using multiple linear regression methods, stunting was a significant predictor of age at menarche. Average energy intake (kcal/d) from home diet was associated with earlier menarche independent of preschool growth status. Percent time ill with diarrhea was positively associated with age at menarche. When the effects of diet, supplement, percent time ill with diarrhea and respiratory illnesses, and SES were taken into account, the independent influence of stunting on age at menarche persisted and remained significant. © 1996 Wiley-Liss, Inc.     

CYP Gene Polymorphisms and Early Menarche

Early age at menarche is a risk factor for breast cancer. A previous study reported a significant positive association between the CYP3A4*1B variant allele and early puberty. We investigated whether polymorphisms of the CYP3A4, CYP17, CYP1B1, and CYP1A2 genes predict the age at onset of menarche. Five hundred eighty-three nulliparous women between ages 17 and 35, of various ethnic backgrounds, completed a questionnaire that included information about menstrual history. Samples of DNA were provided and used to genotype these women for polymorphic variants in the four genes. There was no significant difference in mean age at menarche between women who carried two variant CYP17 A2 alleles (12.5 years) and women who carried one or no variant allele (12.5 years) (P = 0.8, adjusted for ethnic group and year of birth). Similar results were found for the CYP1B1*3 variant allele and for the CYP1A2*1F variant allele. Women who carried two variant CYP3A4*1B alleles had an earlier mean age at menarche (12.0 years) than women who carried one or no variant allele (12.6 years) (P = 0.02). However, after adjusting for ethnic group and year of birth, no significant differences in mean age at menarche were found. The polymorphic variants of the CYP3A4, CYP17, CYP1B1, and CYP1A2 genes are unlikely to influence age of menarche.     

The age at menopause and associated factors at the health center area in Ankara, Turkey

OBJECTIVES: This study is performed in one health center area in Ankara, Turkey on a women population of 50-65 years in order to demonstrate menopausal status of women, age at menopause and factors related with the age at menopause. METHODS: This is a cross-sectional study which has been performed on a women population of 50-65 years. The local population was 17,153 in this area by 2001. All of the household determining forms are screened in order to detect the all of the women who were in 50-65 years group, then name and addresses of the these women's are listed. There were 1089 women aged 50-65 years who were constituting 7% of the population. After choosing the first name randomly from the list of the women, 1/3 systematic sampling method was used and, the number of the women in the sampling was 363 (95% C.I., +/-5% S.E.). The response rate among those eligible women who were contactable during the study was 99% (360/363). Data were collected by interviews through questionnaires. The questionnaire consisted of a series of questions concerning age at menopause, socioeconomic status, age at menarche, age at first pregnancy, regularity of menstrual cycles, parity, duration of breast feeding, use of OCs, BMI, smoking habit, age at menopause of the mother and the sister. Chi-square and t-test methods were used for statistical analyses. RESULTS: 4.2% of the women were in premenopause, 13.3% were in perimenopause, 72.8% were in natural menopause and 9.7% were in surgical menopause. Average age at natural menopause was 47+/-4.2 years. Education, age at menarche, smoking, age at menopause of the mother and the sister were found to be related with the age at menopause. CONCLUSIONS: Ninety-six percent of the women over age of 50 years, are at menopause or perimenopause. The results of this study suggest that, for factors of genetic and age at menarche, there are not many possibilities for the lifestyle changes that would modify age at menopause with the subsequent reduction in risk for chronic diseases, but daughters or sisters of women with an early menopause and women who smoked or less educated could be counselled with respect to family timing.     

SHORT REPORT: Secular trend in age at menarche for women born between 1920 and 1979 in Rio de Janeiro,Brazil

Primary objective: This article presents data on the secular trend in age at menarche for 1955 women from 16 to 76 years of age born between 1920 and 1979 and studied under the Nutrition and Health Survey conducted in the municipality of Rio de Janeiro, Brazil, in 1996.

Methods and procedures: Age at menarche was defined by the retrospective method. Women were grouped according to decade of birth, and the trend was estimated using simple linear regression between age at menarche and year of birth for the following specific periods: 1920-1940, 1920-1960, 1960-1979 and 1920-1979.

Main outcomes and results: Mean age at menarche decreased from 13.07 to 12.40 years when comparing the group of women born in the 1920s with the 1970s birth cohort, corresponding to a mean rate of -0.0123 years per year (p &lt; 0.001). The downward trend was -0.0120 years per year (p &gt; 0.05) for the 1920s, 30s and 40s, -0.0093 years per year (p &lt; 0.05) for the period from 1920 to 1960, and -0.0224 years per year (p &lt; 0.01) for the 1960s/70s.

Conclusions: The results suggest a secular trend in age at menarche. The literature points to such environmental variables as improved living conditions and expanded access to health services. Within this context, age at menarche could be used as a marker for social development.     

Age at menarche in a Chuvashian rural population

OBJECTIVES: The secular trend and familial influences on age at menarche among a rural Chuvashian population was examined in a cross-sectional community-based study. SUBJECTS AND METHODS: The cohort included 617 females aged 18-80 years, with age at menarche ranging from 10 to 24 years (mean 15.4 +/- 2.1). Statistical analyses included simple linear regression, maximum likelihood estimation and a whiskers plot. RESULTS: Women born during the second through the fourth decade of the 20th century showed increasing mean values of age at menarche from 15.4 (second decade) up to 16.5 (fourth decade). Women born after the fourth decade showed a decrease in mean values from 15.5 (fifth decade) to 13.0 (ninth decade). The highest peak of age at menarche was in women born in 1932. Significant familial correlations were observed between adjusted to year of birth age at menarche in mothers and daughters r = 0.195, p<0.01 and sisters and sisters r = 0.404, p<0.01. CONCLUSION: Our study demonstrated the certain secular trends of age at menarche in Chuvashian women who matured after World War II. Periods of socio-economic disasters such as war and famine disrupt the secular trend. Our findings also confirm the hypothesis of significant familial influences on menarcheal age.     

Secular trend in the age at menarche in Haiti

Trends in age at menarche of 10,563 pregnant Haitian women enrolled in a longitudinal study of maternal mortality are examined. Mean recalled age at menarche for adult women in the sample was 15.37 years. However, there was a clear decline in mean menarcheal ages from the oldest to the youngest women, with a mean rate of decline for adult women of 0.36 years per decade. Mean menarcheal age was higher in each age group of rural women than for women in the metropolitan Port-au-Prince area; the rate of decline for adult rural women (0.37 years per decade) was nonsignificantly higher than that for adult metropolitan women (0.30 years per decade). The data suggest a secular decline in age at menarche in Haiti, as well as a continuing disparity between metropolitan and rural women. A declining age at menarche has important implications for fertility and reproductive health in Haiti, and may reflect a gradual improvement in health and nutritional status. © 1995 Wiley-Liss, Inc.     

Uncertainties in designation of age at menarche in the nineteenth century: revised mean for Denmark, 1835

The earliest Danish study of mean age at menarche by Ravn (Fenger 1850) is analysed with special reference to age recordings and their subsequent groupings into age-classes. Uncertainties of interpretation of the age designations are discussed, and it is argued that, in all probability, mean age at menarche was 17 years in the samples of Danish women born around 1820, rather than below 16 years as believed previously.     

Menarcheal age for Norwegian women born 1830–1960

Data from birth records from the maternity hospitals in the three main cities in Norway have been used to study the trend in menarcheal age for women born from about 1830 to about 1960. The investigation is based on a sample of 200–300 records around every 10th year from each of the three clinics in partly overlapping time periods relating to a total of 9152 women. The recollected age at menarche fell from just above 16 years for women born around 1830 to just above 13 years for those born around 1960, the decrease being not totally linear. These results correspond closely with a previously published investigation from Oslo from about the same period of time (Brudevoll, Liestøl and Walløe, 1979), but our results, which cover more of Norway, show a more linearily shaped curve than the results covering only Oslo. We have also analysed the relationships of several independent variables to menarcheal age, using multivariate linear regression methods. Besides the woman's year of birth, which was the most important variable throughout the whole period of time, various geographical variables were found to be of moderate importance. Being born in the countryside and in towns other than Oslo and Bergen led to a slightly higher age at menarche. No significant difference between Oslo, Bergen and Trondheim was detected except for the period up to about 1880 where the Bergen women had about 2·6 months earlier menarche than the Oslo women. Married women amongst the sample had experienced menarche a little earlier than the unmarried, and among married women there was an association between occupation and menarcheal age, women from the lowest social classes having the latest ages at menarche. The importance of these socially related parameters declined with time, and for women born after 1945 the difference seemed to have disappeared. The age at menarche was found to be positively related to a woman's age at first birth; the further back in time the stronger the relation. In addition, delayed age at menarche was also found to be associated with irregularities in the menstrual cycles in later life.     

Social background and age at menarche in Portuguese university students: A note on the secular changes in Portugal

Menarcheal age of a sample of Portuguese university students (n = 3,366), born between 1972 and 1983, age 18–23 years, was analyzed. The influence of parents' educational level and occupation, family size, birth order, and degree of urbanization of girl's locality of residence during childhood and adolescence were analyzed as well as secular trend in the Portuguese population. Mean age at menarche for girls born in 1983 was 12.32 years. Parents' educational level and occupation did not show any significant influence on mean age at menarche. Place of residence during childhood years and adolescence showed a significant effect on mean age at menarche, with girls from rural places with a later age at menarche than those who spent their childhood or adolescence in urban areas (P ≤ 0.01 and P ≤ 0.05 for childhood and adolescence, respectively). Family size and birth order showed the highest effect. Girls born in small families, with one child, matured earlier (12.32 years) than those born in large families with four or more children (12.67 years), (P ≤ 0.01). Also, girls that were first‐born had an earlier menarche (12.41 years) than those who were third or later (12.58 years, P ≤ 0.01). Regression analysis selected family size and place of residence in childhood as the most important determinants of mean age at menarche in our university students. In this sample, from 1972 to 1983, mean age at menarche remained stable. When we considered published data from all the Portuguese population we found a decrease in mean age at menarche from 15 years for girls born in 1880 to 12.44 for those born in the 1980s. This decrease was the result of great improvements in the social and economic living conditions that occurred in Portugal especially after the 1970s concerning nutrition and health care, among many other environmental factors. Am. J. Hum. Biol. 15:415–427, 2003. ©2003 Wiley‐Liss, Inc.