[Age at menarche among schoolgirls from a rural community in Southeast Brazil]

Nutritional status and age at menarche in amazonian students

OBJECTIVES

Age at menarche (MA) is a proxy for biological maturation and a parameter of socioeconomic changes. Worldwide, anticipation of menarche is associated with nutritional transition and excess weight. The objective of this study was to evaluate the MA in Amazonian students and its association with nutritional status, ethnicity, and socioeconomic level.

METHODS

Cross-sectional study with 1,017 students aged 6 to 17 living in the city of Manaus, Brazil. MA was analyzed by status quo and recall; its association with body mass index (BMI), race, socioeconomic status, and adult height was examined.

RESULTS

559 (51.9%) participants had already experienced menarche. In 91.7%, menarche occurred between 10 and 14 years of age; the mean age at the onset of menarche was 11.9 years. Overweight (11.6 years) and obese (11.4 years) participants reached menarche earlier than those with normal weight (12 years) and lean (12.7 years) participants. The associations between MA and nutritional status showed that overweight and obesity are risk factors for the early occurrence of menarche. MA was not associated with socioeconomic status/parental education or race. However, excess weight was associated with earlier MA in all races and social classes. The adult height was slightly lower in girls with menarche before 12 years old (157.9 vs 159.4 cm).

CONCLUSION

Regardless of socioeconomic level or ethnicity, excess weight was associated with earlier menarche in Amazonian students.

Father absence and reproduction-related outcomes in Malaysia, a transitional fertility population

Father absence is consistently associated with children’s reproductive outcomes in industrialized countries. It has been suggested that father absence acts as a cue to particular environmental conditions that influence life history strategies. Much less is known, however, about the effects of father absence on such outcomes in lower-income countries. Using data from the 1988 Malaysian Family Life Survey (n = 567), we tested the effect of father absence on daughters’ age at menarche, first marriage, and first birth; parity progression rates; and desired completed family size in Malaysia, a country undergoing an economic and fertility transition. Father absence during later childhood (ages 8 to 15), although not during earlier childhood, was associated with earlier progressions to first marriage and first birth, after controlling for other confounders. Father absence does not affect age at menarche, desired family size, or progression from first to second birth. The patterns found in this transitional population partly mirror those in developed societies, where father absence accelerates reproductive events. There is, however, a notable contrast between the acceleration in menarche for father-absent girls consistently found in developed societies and the lack of any association in our findings. The mechanisms through which father absence affects reproduction may differ in different ecological contexts. In lower-income contexts, direct paternal investment or influence may be of more importance in determining reproductive behavior than whether fathers act as a cue to environmental conditions.

Socioeconomic status and age at menarche in indigenous and non-indigenous Chilean adolescents

The objective was to analyze the relationship between socioeconomic status and age at menarche among indigenous and non-indigenous girls in the Araucanía Region of Chile, controlling for nutritional status and mother's age at menarche. A total of 8,624 randomly selected girls from 168 schools were screened, resulting in the selection of 207 indigenous and 200 non-indigenous girls who had recently experienced menarche. Age at menarche was 149.6 ± 10.7 months in the indigenous group and 146.6 ± 10.8 months in the non-indigenous group. Among the non-indigenous, the analysis showed no significant association between age at menarche and socioeconomic status. In the indigenous group, age at menarche among girls with low socioeconomic status was 5.4 months later than among those with higher socioeconomic status. There were no differences in nutritional status according to socioeconomic level. Obesity was associated with earlier menarche. Menarche occurred earlier than in previous generations. An inverse relationship between socioeconomic status and age at menarche was seen in the indigenous group only; low socioeconomic status was associated with delayed menarche, regardless of nutritional status or mother's age at menarche.

Investimento materno e história reprodutiva de mães residentes em contextos com diferentes graus de urbanização

A presente pesquisa tem como objetivo caracterizar o investimento materno e a história reprodutiva de mães que vivem em diferentes contextos. Para tal, 150 mães que residiam em três contextos com diferentes graus de urbanização foram entrevistadas. Por meio da análise estatística dos dados constatou-se que houve diferenças significativas entre os contextos, além de correlações positivas entre os núcleos reprodutivos, como idade da primeira relação sexual e idade da mãe no nascimento do primeiro filho. Conclui-se que as estratégias reprodutivas são influenciadas pela história de vida das mães, das condições sociodemográficas atuais e do contexto onde vivem.

Premenstrual symptoms and syndrome according to age at menarche in a 1982 birth cohort in southern Brazil

Premenstrual symptoms and syndrome were studied in young women who have been followed since birth. Data were collected on the intensity of four symptoms: irritability, anxiety or stress, depressed mood, and affective lability. Premenstrual syndrome was defined according to intensity of symptoms. Association between age at menarche and premenstrual symptoms and syndrome were investigated through Poisson regression. Adjusted analysis was conducted, controlling for possible confounding factors. The symptoms most frequently reported by the women from the 1982 Pelotas, Rio Grande do Sul, Brazil, birth cohort who were interviewed in 2004-2005 were: irritability (52.3%) and anxiety (40.2%). The prevalence rates for moderate and severe premenstrual syndrome were 13.4% and 5.8%, respectively. Mean age at menarche was 12.4 (+/-1.5) years. Prevalence rates for symptoms and premenstrual syndrome were higher in women whose age at menarche was less than 11 years, but this difference was not statistically significant. Information on symptoms and premenstrual syndrome is scarce in other studies.

Investimento parental e desenvolvimento da criança

Segundo a teoria do investimento parental, seria esperada uma relação entre condições de criação da mãe e sua carreira reprodutiva e, por conseqüência, seus padrões de cuidado aos filhos, com repercussões no desenvolvimento das crianças. Esta pesquisa buscou verificar essas relações, em amostra de 37 mães e seus filhos entre um e quatro anos, de um bairro pobre de Salvador, Bahia. Foi investigada a história familiar e reprodutiva das mães, associada a resultados desenvolvimentais das crianças, medidos através das escalas Bayley e WIPPSI-R, em quatro avaliações realizadas ao longo de três anos. Foram encontradas correlações entre condições de criação da mãe e sua carreira reprodutiva subseqüente. Por sua vez, esses padrões mostraram-se modestamente relacionados ao desenvolvimento cognitivo de seus filhos, favorecendo as crianças cujas mães iniciaram sua vida reprodutiva mais tarde. Os resultados são, em geral, compatíveis com a teoria do investimento parental. Limitações do estudo e perspectivas futuras são discutidas.

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.

Socio-demographic predictors of age at menarche in a group of Colombian university women

BACKGROUND

Age at menarche is an important developmental milestone known to be modified by social and environmental factors. The determinants and potential change over time of age at menarche in Colombia are not well documented.

AIMS

To obtain a current estimate of age at menarche in Colombia and to examine the associations between socio-demographic characteristics and age at menarche.

SUBJECTS AND METHODS

Between 1998 and 2001, we obtained recalled age at menarche, socio-demographic characteristics, and physical activity information in a group of 3206 students at the National University of Colombia who completed a self-administered questionnaire. We examined the cross-sectional associations between mean age at menarche and migratory pattern, parental education, socio-economic status indicators, practice of physical activity, and year of birth using linear regression.

RESULTS

Mean age at menarche (+/- SD) was 12.68 +/- 1.31. In a multivariate adjusted regression model, age at menarche was positively associated with family size and the practice of at least 2 daily hours of physical activity, and was inversely related to urbanization level, socio-economic status, and year of birth.

CONCLUSIONS

Socio-economic status is a strong predictor of menarche in this population. There appears to be a trend towards earlier menarche by year of birth.

Effects of different socioeconomic conditions on menarche in Turkish female students

PURPOSE

The aim of this study was to determine the age at menarche, the menarcheal features, and the association between menarcheal age and socioeconomic status in an urban area in Turkey. In addition, we tried to assess whether there is a relationship between age at menarche and body composition.

METHODS

We asked some questions about menarche of 1017 female adolescent students in the high schools of Manisa region. Height and weight were measured. The body mass index (BMI; kg/m2) was used as an index of relative weight. Adolescent girls were grouped into three socioeconomic status according to the educational and occupational levels of their parents. The age at menarche and the menarcheal pattern were evaluated according to the socioeconomic status.

RESULTS

The ages of girls involved in the study ranged between 14 and 18 years, with a mean of 15.7+/-1.1 years. Although the menarcheal age was found to be lower in girls with higher socioeconomic status, there was no significant difference between the three different socioeconomic status. In all of the three groups, menarche was more common in summer and fall than in spring and winter. Although the mother was an important source of knowledge in all groups, it was significantly more important in the group with high socioeconomic status. Adolescent girls with low socioeconomic status had fewer premenstrual complaints. However, there was no significant difference between the groups. We found an inverse correlation between menarcheal age and postmenarcheal weight and the BMI (r=-0.14, p=0.000). However, there was no correlation between menarcheal age and postmenarcheal height.

CONCLUSION

These results indicate that as the social status differences decrease, the difference observed in menarcheal age and pattern disappears in urban areas of developing countries. Menarcheal age may be an indicator of socioeconomic development. It does not influence postmenarcheal height; however, as menarcheal age decreases, BMI increases.

Monthly distribution of menarche among schoolgirls from a municipality in Southeastern Brazil

We studied the monthly distribution of menarche among schoolgirls from Barrinha, Brazil, a municipality of rural characteristics in the process of transition to urbanization, economically dependent on sugar cane culture and processing. The association between season of the year, month of the year, and birth month and the occurrence of menarche was evaluated. The schoolgirls who provided the date of menarche (month and year) by the recall method and who had menarche up to 36 months before the interview were selected for analysis (460 girls). The correlations between month of occurrence of menarche and month of birth and between menarche and seasons of the year were determined by the chi-square test and the mean monthly ages at menarche were compared by Student's t-test, with a significance level of 0.05. There was a correlation between month of birth and month at menarche, with a peak of occurrence of menarche in December not affected by the menstruating patterns of maturation, but no correlation between menarche and seasons of the year. The difference between mean age at menarche in December (spring-summer transition) and in June (autumn-winter transition) was not significant. Mean age at menarche during the month following school vacations was lower. We conclude that situations of stress-relaxation transition, such as end of the school year, beginning of school vacation, and, perhaps most important, the socioeconomic factor-the end of the sugar cane harvest, when rural workers receive their final payments-favor the occurrence of the peak of menarche in December.