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 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.     

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.     

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.     

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.     

Secular change in age at menarche in rural Oaxaca, southern Mexico: 1968--2000

OBJECTIVE: To evaluate secular change in the age at menarche between 1978 and 2000 in residents of a rural Zapotec-speaking community in Oaxaca, southern Mexico, using status quo and retrospective methods. MATERIALS AND METHODS: Status quo menarcheal status of girls 9-18 years of age in 1978 (n= 101) and 2000 (n=238) and retrospective ages at menarche of adult women 19+ years of age in 1978 (n = 228) and 2000 (n = 246) were obtained via interview. Probit analysis was used to estimate median ages at menarche and 95% confidence intervals (CI) for the status quo data. Analysis of variance and linear regression was used to compare the retrospective data across surveys. RESULTS: The median ages at menarche of adolescents are 14.8+/-1.2 years (0.24 year, 95% CI 14.2-15.4 years) in 1978 and 13.0+/-1.0 years (0.10 year, 95% CI 12.7-13.3 years) in 2000. Age at menarche has declined by 1.8 years over about 23 years, 0.78 year/decade (95% CI = 0.65-0.91 year/decade). Recalled ages at menarche do not differ by age group in the 1978 survey, but differ significantly by age group in the 2000 survey (p <0.001). Within the 2000 survey, the two youngest age groups (< 29, 30-39 years) do not differ, but attain menarche earlier than women in the four older age groups (p < 0.05), who do not differ from each other in age at menarche. The estimated rates of secular decline in age at menarche in adult women vary between 0.38 and 0.42 years/decade (0.26-0.56 year/decade). CONCLUSIONS: There is a major secular decline in the age at menarche of adolescent girls and young adult women between 1978 and 2000. The estimated rate of decline in adult women is about one-half of that in adolescent girls. The secular decline in age at menarche is consistent with corresponding secular gains height, sitting height and estimated leg length of children and adolescents in the community; corresponding secular gains are smaller in young adults 19-29 years.     

Season of birth influences the timing of menopause

BACKGROUND: Seasons may influence prenatal growth and future fertility. This study investigated whether season and month of birth influenced the timing of menopause in a group of women attending three Italian menopause clinics. METHODS and RESULTS: Age at menopause of 2822 post-menopausal women (>12 months of amenorrhoea) was stratified by month and season of birth. Mean age at menopause was 49.42 years (SEM: 0.78 years). Menopause occurred earlier for women born in the spring (age 49.04+/-0.15 years) than in the autumn (49.97+/-0.14 years). The earliest menopause was found in women born in March (48.9+/-0.25 years) and the latest in women born in October (50.3+/-0.25 years). The effect of season of birth on age at menopause remained even when considering factors that in our analysis were capable of significantly interfering with the timing of menopause, such as age at menarche, body mass index, smoking habit, level of education and type of job. CONCLUSIONS: Taking into consideration the retrospective design of the study, and a possible recall bias, the present data seem to suggest that environmental factors linked to seasons are capable of interfering with the timing of a woman's ovarian exhaustion by an action exerted in the prenatal period.     

Family socio-economic background modified secular trends in age at menarche: evidence from the Pró-Saúde Study (Rio de Janeiro,Brazil)

BACKGROUND: Since age at menarche has been associated with socio-economic status, its downward secular trend might vary according to the different socio-economic status levels of the family in which women lived during their childhood. AIM: This study seeks to describe secular trends in age at menarche for Brazilian women whose fathers had different levels of educational attainment. SUBJECTS AND METHODS: A self-administered questionnaire was applied to 2053 women born between 1931 and 1977. Multiple linear regression models were employed to estimate trends in age at menarche according to categories of educational level of the participants' father. RESULTS: The age at first menstruation varied from 7 to 19 years, with a mean age of 12.3 years (+/- 1.64 SD). The reduction in age at menarche was 2.4 months per decade for all women. Among daughters of fathers with less than 8 years of schooling this reduction was 3.6 months per decade, and among daughters of fathers with 8 years or more of study it was 1.2 months per decade. CONCLUSION: Improvements in living conditions in Brazil over the last decades seem to have had a stronger effect on the reduction of the age at menarche among women who lived their childhood in worse socio-economic standards.     

Are the effects of risk factors for timing of menopause modified by age? Results from a British birth cohort study

OBJECTIVES: This study investigated the influence of mother's age at menopause, early life and adult behavioral factors on the timing of menopause until age 57 years, and whether these effects vary according to the women's age at menopause. DESIGN: A nationally representative cohort of 1,583 British women born in March 1946 with prospective data across the life course. For factors that vary with age at menopause, analyses were stratified by age at menopause younger than 50 years or 50 years or older. RESULTS: Cox regression models indicated that for women with earlier menopause, those who were heaviest at 2 years had a 59% lower hazard ratio for menopause than those who were the lightest (hazard ratio [HR]=0.41, 95% CI: 0.16-1.01), whereas this figure was 35% lower (HR=0.65; 95% CI: 0.42-1.00) for the later menopause group. For women in the earlier group with parental divorce during childhood, the HR was 6.5 (95% CI: 2.021.3) times higher than that of other women. This rate decreased to 2.5 (95% CI: 1.5-4.2) for those with later menopause. In both groups, increasing mother's age at menopause was associated with decreasing HR (P<0.0001). For all women, being breast-fed (P=0.05), increasing cognitive ability (P=0.009), and increasing parity (P=0.001) delayed menopause. CONCLUSIONS: This study found that the impact of weight at 2 years, parental divorce during childhood, and mother's age at menopause varied according to the women's age at menopause. There was further evidence that being breast-fed, higher childhood cognitive ability, and increasing parity delayed menopause. These results suggest the interaction of genetic and environmental factors in determining age at menopause.     

Recent decline in age at menarche: The Fels Longitudinal Study

A number of recent reports suggest that the average age at menarche of US girls has declined over the past 20 years. Because the putative declines in the age at menarche are concurrent with increases in childhood body mass index (BMI), it has been suggested that these two trends may be causally linked. We examined differences in mean age of menarche in Fels Longitudinal Study girls who were born in six 10‐year birth cohorts (1930s, 1940s, 1950s, 1960s, 1970s, and 1980s) and simultaneous cohort changes in mean BMI measured cross‐sectionally at selected ages from 3–35 years (n = 371). Girls born in the 1980s had a mean age at menarche of 12.34 years, which was ～3–6 months earlier than that of girls born previously (P < 0.001). While the mean BMI values at ages 25 and 35 generally increased from the 1930s to the 1970s, the mean BMI during childhood and adolescence remained constant across the six birth cohorts. In summary, we found no evidence that the recent decline in the age at menarche in the Fels Longitudinal Study girls was reflected in concurrent increases in BMI at any point in childhood or adolescence. Conversely, girls born in the 1960s and 1970s have subsequently become heavier in young and mid‐adulthood than were girls from earlier birth cohorts, without any concurrent change in the mean age at menarche over that time period. These two findings suggest that population‐level shifts in BMI and the timing of menarche are largely independent, although sometimes coincident, processes. Am. J. Hum. Biol. 16:453–457, 2004. © 2004 Wiley‐Liss, Inc.     

Caloric restriction reduces age at menopause: the effect of the 1944-1945 Dutch famine

OBJECTIVE: To assess the effect of caloric restriction, as endured during the 1944-1945 Dutch famine, on the age at which natural menopause occurs and to identify specific vulnerable age periods in which caloric restriction has the largest effect. DESIGN: This was a population-based cohort study conducted in Utrecht, the Netherlands. Between 1983 and 1986, 9,471 women aged 40 to 73 years at the time of interview were classified regarding their exposure to the famine. Age at natural menopause was obtained from all available data, retrospectively as well as prospectively. We estimated differences in mean age at natural menopause between famine exposure categories (not, moderately, and severely exposed), with adjustment for smoking, parity, socioeconomic status, body mass index, age at menarche, and year of birth. RESULTS: Women experienced natural menopause on average 0.36 years earlier (95% CI: -0.60, -0.11) when severely exposed to the famine and 0.06 years earlier (95% CI: -0.22, 0.09) when moderately exposed compared with the unexposed women. This effect was particularly pronounced in those severely exposed from 2 to 6 years of age: -1.83 years (95% CI: -3.03, -0.63). CONCLUSIONS: Our findings suggest that caloric restriction decreases age at natural menopause. Early childhood seems to be a particularly sensitive age period for this effect.     

Variability of reproductive history across the Swiss SAPALDIA cohort--patterns and main determinants

BACKGROUND: Reproductive characteristics play an aetiological role for many diseases, including reproductive cancers. They have been shown to vary internationally and nationally, but have not yet been described for the whole Swiss population. AIM: The study investigated the variability of reproductive characteristics, their patterns, and main determinants across a population-based female study population in Switzerland. METHODS: Reproductive characteristics obtained from 3119 women (28-72 years) participating in the SAPALDIA cohort survey in 2001-2003 are described across birth cohorts, study areas, language regions, and levels of urbanization. Determinants of age at menopause were analysed by Cox regression. RESULTS: Reported median age at menarche was 13 years and median age at natural menopause was 52 years. The prevalence of nulliparity was 27%, and the fertility rate 1.6. Across birth cohorts there was a decline of menarcheal age and fertility rates, and an increase of nulliparity and age at last pregnancy. All characteristics varied across study areas, language regions, and levels of urbanization. Smoking, parity, and physical exercise were stronger predictors of earlier (<52 years) than older (>52 years) menopausal age. CONCLUSION: Reproductive events show secular and geographic variation within Switzerland. Smoking, parity and physical activity significantly predict age at natural menopause, particularly before age 52. The secular trend of earlier menarche and increased nulliparity may result in a higher risk of reproductive cancers in younger generations.     

Age at menarche in Flemish girls: current status and secular change in the 20th century

The age at menarche in a national sample of 4894 Flemish schoolgirls was surveyed in 1979-1980. The probit estimate of the mean age at menarche was 13.20 +/- 0.02 years (SD = 1.25 years). This estimate falls well within the range of reported ages at menarche for girls in northwestern Europe, but is slightly later than those for French-speaking girls in Belgium and in France. Status quo secular data for the 20th century indicate a decline in estimated mean ages at menarche of Flemish girls from about 14.3 years before World War II to 13.6 and 13.2 years, respectively, among girls born just before and during the war. Subsequently, mean ages at menarche of Flemish girls are fairly stable between 13.0 and 13.2 years. These secular changes are of the same magnitude as those observed in other European countries.     

Childhood cognitive ability and age at menopause: evidence from two cohort studies

OBJECTIVE: To investigate whether poorer cognitive ability in childhood is associated with an earlier menopause. DESIGN: Two cohorts were included: a nationally representative British birth cohort study of 1,350 women born in March 1946 and followed up to age 54 years, and an Aberdeen cohort study of 3,465 women born in Aberdeen from 1950 to 1956 and followed up to age 44 to 50 years. Both cohorts had prospective information on childhood cognitive ability at age 7 or 8 years. RESULTS: In both cohorts, women with lower cognitive scores in childhood reached menopause earlier than women with higher scores. With follow-up of menopause to 49 years, the hazard ratio (HR) for one standard deviation of the cognitive score was 0.80 (95% CI, 0.72-0.90) in the Aberdeen cohort and 0.84 (95% CI, 0.73-0.97) in the older 1946 birth cohort. The effect was still evident in the 1946 birth cohort with follow-up of menopause to 53 years (HR = 0.87; 95% CI, 0.79-0.95). These ratios were weakly attenuated by adjustment for potential confounding effects of lifetime socioeconomic circumstances, parity, and smoking. CONCLUSIONS: The association between early cognitive ability and timing of menopause only partially reflects common risk factors, although residual confounding remains a possibility. Alternatively, early environmental or genetic programming may explain this association, perhaps through setting lifelong patterns of hormone release or causing transient hormonal changes at sensitive periods of development. These findings have implications for the interpretation of studies investigating an association between age at menopause and adult cognitive function.     

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.     

Secular trends in age at menarche among Caboclo populations from Pará, Amazonia, Brazil: 1930-1980.

The present study is part of a large research project on growth, development, nutrition, and health of Caboclo populations from the Brazilian Amazon. The aim of this paper is to analyze the age of menarche in adolescents (N=164) and adult women (219) in the studied populations. Caboclo are admixed rural, peasant groups that live along the Amazon river and its tributaries, and there are few previous studies about them. Probit analysis of the status quo data yielded a median age at menarche of 12.29+/-1.76 years. The retrospective method was applied to recall data of the 77 post-menarcheal adolescents, yielding an average of 13.06+/-1.27 years. Number of children in the family did not show any statistical influence on age at menarche in any age group. In adult women, age at menarche decreased from 14.50 in those born in 1930 to 12.88 for those born in 1980 (F=4.371, P=0.001). The downward trend found was, on average, 0.237 year per decade in the study period. The median age at menarche in the adolescents (12.29 years) is one of the lowest values found for Central and South American populations. In the ecological context, a low age at menarche could be an adaptive advantage because it provides a greater chance for reproduction at a young age in an environment where, until recently, life expectancy was low. As has been reported for other developing countries, the change found in age at menarche in the women born from the 1930s to the 1980s is likely to be related to changes in health and nutritional factors that occurred in Brazil because this country experienced significant improvement in living standards related to education, vaccination, and health conditions, which, although not equally, reached all regions after the 1960s.     

Age‐Related Changes in Bone‐Strength‐Associated Geometry Indices in Naive Human Population

The aim of the present study was to evaluate age‐ and sex‐related changes in the geometry parameters (metacarpal cortical index (MCI) and Breaking Bending Resistance Index [BBRI]) of long hand bones in a large Chuvashian cohort using cross‐sectional and longitudinal study designs. The data were gathered in 1994 (557 individuals) and 2002 (513 individuals). The latter sample included 260 individuals who were studied only during the second expedition, and 253 individuals who were previously investigated in 1994. Statistical analyses included a maximum likelihood‐based model‐fitting technique and a t‐test comparison. Our study describes age‐related MCI and BBRI changes in both sexes from the age of 18 years to 84 years. At any age, the BBRI values were higher in males than in females, but MCI was greater in females than in males before age 50 and lower after that age. The study provides initial evidence of a secular trend in MCI and BBRI. In male hand bones, the cortex became relatively thicker and it better resisted bending and breaking in comparison to individuals born at the beginning of the 20th century. In females, the trend toward higher MCI values can be observed only in those born between 1936 and 1966 and the trend toward higher BBRI values stopped in 1950. Anat Rec, 291:835‐844, 2008. © 2008 Wiley‐Liss, Inc.     

Age at menopause and cause-specific mortality in South Korean women: Kangwha Cohort Study

OBJECTIVE: The purpose of this study was to examine the relation between age at natural menopause and all-cause and cause-specific mortality among women. METHODS: This study used the data of the Kangwha Cohort that was followed up from 1985 to 2001, in particular, for the group of 55 years or older women (n=2658). We calculated the hazard ratio of mortality by the group of age at menopause using the Cox proportional hazards model with adjustment for age, alcohol consumption, education, age at first birth, self-cognitive health level, chronic disease, marital partner, parity, age at menarche, oral contraceptive use and hypertension. RESULTS: The mean (standard deviation) age at menopause was 46.9 (4.9) years, and the median age was 48 years. After adjusting for the relevant variables, the risk of total death in the early menopause group (<40 years at menopause) was 1.32 times higher than that of the reference group (45-49 years at menopause) (95% confidence interval [CI], 1.05-1.66, p=0.02). For the early menopause group, relative to the reference group, the adjusted hazard ratios of death due to cardiovascular disease and cancer were 1.53 (95% CI, 1.00-2.39, p=0.04) and 2.01 (95% CI, 1.06-3.82, p=0.03), respectively. CONCLUSION: Through this study, the age at menopause was found to be different between Asian and Caucasian women and the association of age at menopause with death, particularly caused by cardiovascular disease and cancer, was validated. Our study is one of rare studies regarding the age at menopause of Asian women and their risk of mortality, which could be considered to be meaningful.     

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.