Age at menarche in Ceylon

The age at menarche in girls in schools in Colombo city, Ceylon, in 1968, was estimated by probit analysis as 13·72 ± 0·12 years. This figure is higher than that of 12·84 years obtained in 1950 by a similar analysis. The exact date at menarche was forgotten by 15·5% of the sample but all alleged they remembered the year of age at which it was reached. However, cohort analysis gave a higher mean value than probit analysis, indicating that some girls recollected wrongly, even though special ceremonies attend the event in Ceylon.     

Age at menarche in Iran

Background : Age at menarche and its potential associated factors are reported for 1862 Shiraz (Southern Iran) secondary school girls taking part in a cross-sectional survey selected from the four educational districts of the city. Methods : Probit analysis was used to estimate age at menarche, principal component analysis (PCA) was applied to analyse socio-economic status (SES). Body mass index (BMI) was used as an indicator of nutrition. Results : Mean &#45 SD age at menarche was 12.91 &#45 1.23 years (95% CI: 12.84-12.97). Of all subjects, 33.7% first menstruated in summer. The highest mean age at menarche was 13.01 years in winter. Stress, anxiety and discomfort was seen among 70.3% of subjects at menarche indicating total or partial ignorance of the menstruation phenomenon. Age at menarche decreased as SES improved. Menarcheal age was delayed for underweight subjects. Conclusions : It is concluded that BMI and SES had the most significant effects on variation of menarcheal age in a unified statistical model. However, their interaction was found to be not statistically significant.     

Age at menarche in Iran

BACKGROUND: Age at menarche and its potential associated factors are reported for 1862 Shiraz (Southern Iran) secondary school girls taking part in a cross-sectional survey selected from the four educational districts of the city. METHODS: Probit analysis was used to estimate age at menarche, principal component analysis (PCA) was applied to analyse socio-economic status (SES). Body mass index (BMI) was used as an indicator of nutrition. RESULTS: Mean +/- SD age at menarche was 12.91 +/- 1.23 years (95% CI: 12.84-12.97). Of all subjects, 33.7% first menstruated in summer. The highest mean age at menarche was 13.01 years in winter. Stress, anxiety and discomfort was seen among 70.3% of subjects at menarche indicating total or partial ignorance of the menstruation phenomenon. Age at menarche decreased as SES improved. Menarcheal age was delayed for underweight subjects. CONCLUSIONS: It is concluded that BMI and SES had the most significant effects on variation of menarcheal age in a unified statistical model. However, their interaction was found to be not statistically significant.     

Age at menarche in Greek girls

This study reports menarcheal age in 1134 contemporary Greek girls and the duration of their menstrual cycle. Comparison with a similar study performed 15 years ago shows that in Greek girls there is still a secular trend, although a small one, towards earlier menarcheal age.     

Age at menarche in deaf girls

Using the status quo and retrospective methods, age at menarche was estimated for a sample of 212 deaf girls 7 through 20 years of age. Median age at menarche via probit analysis was 11·91 ± 0·25 years, while the mean based on recalled age in older girls (≥ 15·5 years) was 12·56 ± 0·16 years. These two estimates thus differ by approximately 0·6 years. The probit estimate of median age at menarche in deaf girls is similar to mean ages reported for blind girls. However, the retrospective age is later. Thus, the present data are inconclusive as to whether the sensory deprivation imposed by deafness has an accelerating effect on menarche similar to that hypothesized for light deprivation in blind girls.     

Age at menarche in rural France

Data upon age at menarche have been collected among 254 schoolgirls of a relatively endogamous rural population in central France. The median age at menarche estimated by probits was 13·05±0·18, SD1·42. This accords well with results obtained from urban samples in the years 1965–68. Both rural and urban samples give a median age 0·5 year earlier than data from a national survey performed in 1950.     

Age at menarche on a small Bahamian island

Age at menarche in the rather highly inbred population of a small island in the Bahamas has been estimated through the recollection of adult women. It averages 14.5 years for women over 40 and 14.1 years for women under 40.     

Age at menarche and cancer risk at adulthood

Aim: The aim was to evaluate the association between age at menarche and cancer using a nationally representative sample of Brazilian women.

Methods: Data from the Brazilian Health Survey (PNS), a nationally representative survey conducted in 2013 (n?=?33,715 women;?≥18 years), were used. Information on cancer diagnosis, age at menarche and other co-variables (chronological age, educational status, skin colour, menopause, leisure-time physical activity and tobacco smoking) were collected via interview. Logistic regression models were used for aetiological analyses.

Results: The prevalence of cancer diagnosis was greater among women with early age at menarche [2.6% (2.0–3.5%)] compared to on-time [1.6% (1.4–1.9%)] and late women [2.0% (1.1–3.4%)]. The onset of menarche ≤11 years was significantly associated with cancer risk, regardless of co-variables [OR =2.45 (1.34–4.48)], compared to the late group.

Conclusion: Early age at menarche was associated with cancer risk in adulthood, regardless of race, educational status, chronological age, obesity, menopause onset, tobacco smoking or physical activity.     

Age at menarche in Sardinia (Italy)

The median age at menarche in 1080 Sardinian girls (ages 11.00-16.49 years) was calculated with the status quo method and probit analysis as 12.78 +/- 0.06 years.     

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.     

Age at menarche of schoolgirls in Maputo,Mozambique

Age at menarche was analysed in 753 Mozambican schoolgirls taking part in across-sectional anthropometric study in Maputo, Mozambique, in 2000. The probit analysis of the status quo data yielded an median age at menarche of 13.20 +/- 1.18 years. The retrospective method was applied only to recall data of the 396 post-menarcheal girls and it yielded an average of 13.91 +/- 1.29 years. Mean age at menarche in girls living in the urban centre of Maputo was 13.35 and 12.96 years, for recall age and probit analysis, respectively, and 14.51 and 13.68 years for girls living in the slums surrounding the centre. The differences in age at menarche, calculated by recall method, between girls from central Maputo and girls from the slums were statistically significant (p = 0.000). Parent's educational level also revealed a significant effect on age at menarche. Girls whose parents had a lower educational level showed a later age at menarche. For the size of the family, girls who were later borne had a higher age at menarche. In the 1960s, the age at menarche was 13.55 and 13.83 years in urban and rural girls, respectively. In this study, we found a lack of decrease in the mean age at menarche (13.9 years), which could be due to the poor living conditions in Mozambique between 1960 and 2000 as a result of the civil war from 1976 to 1990. Despite the economic growth of the country in the last decade, Mozambique is still in the group of the poorest countries in the world; in spite of this fact, the mean menarcheal age in these girls are amongst the lowest values presented for African countries.     

Age at menarche and postmenarcheal growth in rural Bangladeshi females

This study examines the role of chronological age and time since menarche (TSM) as determinants of postmenarcheal growth in height and weight in a chronically malnourished population of rural Bangladeshi females aged 10-20 years. Height and weight measurements were collected for 12 months from 290 postmenarcheal girls, with known times since menarche, and on 118 girls who reached menarche during the one year follow-up. Two stage regression analysis was employed to study the relationship of age and time since menarche to postmenarcheal growth in height and weight, while adjusting for socioeconomic status. TSM is a more important determinant of postmenarcheal growth in height and weight than is age. For postmenarcheal growth in weight, the regression coefficient for TSM is six times greater then the coefficient for age. The effect of TSM was twice as strong as the age effect for postmenarcheal growth in height. Age has a statistically significant negative influence on statural growth and weight gain, but its practical effect on weight gain is small. An interaction between TSM and age suggests that TSM does not have the same implications for biological maturity for all ages at menarche. Findings demonstrate that Bangladeshi adolescents are still in active growth in height and weight into their late teens and past 20 years in some girls. This extended growth period may pose increased health risks to young mothers and their offspring.     

Age at menarche in Sri Lankan Tamil girls in Jaffna

Using the status-quo method and Probit analysis, the median age at menarche of Sri Lankan Tamil girls (N = 333) from a middle socio-economic group was estimated as 13.78 +/- 0.07 years with a standard deviation of 1.01 years. This is about one year later than the median for the urban and about six months earlier than the median for the rural girls of Sri Lanka of the 1950s. However, this median age estimate agrees well with the results of an urban Madras sample. The reliability of the present finding is discussed.     

Age at menarche in relation to adult body size and physique

The relationship of early and late menarche with adult body dimensions has been studied on a sample of 147 young adult women drawn from an urban Punjabi population of Chandigarh and Ludhiana. The results indicate that girls with early menarche (age 10 to 11) have significantly smaller skeletal dimensions (both longitudinal and transverse) and more subcutaneous fat than those with average or late menarche. The girls with late menarche have on average more height for weight than early maturers. Results indicate that there is a biological determinant of the observed association between menarcheal age and fatness and adult body size.