Factors influencing the age of menarchePratibha R Vaidya, Nargish D Motashaw
Department of Obstetric & Gynaecology, K.E.M. Hospital and Seth G. S. Medical College, Bombay 400012., India
Correspondence Address: Source of Support: None, Conflict of Interest: None PMID: 1032680
Source of Support: None, Conflict of Interest: None
1. Mean age o f menarche was 14.2 years in a group o f 418 girls.
Menarche is the most important event among the various pubertal changes in girls. The menarchal age seems to be determined by the complex mixture of hereditary and environmental factors. Socioeconomic factors play an important role in the reproductive performance of any woman. It is interesting to study the effects of various socio-economic factors influencing the age of menarche.
Data about the exact age of menarche was collected from 418 girls. This included 134 medical students, 70 selected subjects from O.P.D. and 214 nurses. The data was analysed for the age of menarche in relation to the family income, total number of sisters, total number of siblings in the family, diet and presence or absence of outdoor activities.
[Table 1] shows the means and standard deviations of the age of menarche in the three groups.
The mean age of menarche for nurses was significantly higher than the menarchal age for medical students. The probability is less than 0.001 and is highly significant. It is difficult to explain the fact that the mean age of highly selected patients from O.P.D. was approaching that of medical students. This can be explained partly by the high selection of the persons, as the general O.P.D. patients usually cannot give their exact age of menarche and partly by the fact that most of this selected group were residing in Bombay since childhood. This suggests that the age of menarche is related to the socio-economic conditions as the socio-economic situation of the medical students in on the whole far better than that of the nurses. However, the difference between the medical students and the selected O.P.D group is not statistically significant.
The importance of this difference in the age of menarche is further stressed in [Table 2],which shows the frequency distribution of the age of menarche in the three groups
The economic factors influencing the age of menarche is further stressed in [Table 3].
As the family income at the time of puberty increases, the age of menarche decreases. The difference in the age of menarche per family income is statistically highly significant with p<0.001.
[Table 4] shows the relation of age of menarche to food habits.
There is no correlation between food habits and the age of menarche.
[Table 5] shows the relation of the level of physical activity to the age of menarche.
There was no correlation between the outdoor activities and the age of menarche.
[Table 6] shows the relation between the age of menarche to the number of sisters the respondents had.
The correlation between the number of sisters and the age of menarche is statistically significant with p<0.05. Persons having less than 3 sisters have menarche at an earlier age compared to persons having 3 or more sisters.
[Table 7] shows the relation between age of menarche to the total number of sibs of the respondent.
The age of menarche is related to the total sibs and is less in those having 3 or fewer sibs than in those having more than 3 sibs.
[Table 8] shows the relation between the age of menarche and the place of residence.
Those staying at village and taluka places have higher age of menarche than those staying at towns and at cities. Most of the medical students and O.P.D. group of subjects were staying in Bombay.
Hence when the group of nurses only was analysed, there was a distinct correlation again confirming the above fact.
Our mean age of menarche is slightly higher than that described by Sara Israel  as 13.4 years. In Sara Israel's cases  , 87% had menarche at 12-15 years of age and 33% had their menarche at 13 years. In our cases, 91% of medical students and 84% selected O.P.D. group of cases had their menarche at 11 to 15 years of age but only 47% of nurses had menarche at this age.
There was a high correlation between the socio-economic factors and the age of menarche. This is also reported by Bjolen et a1,  who found that the age of menarche was 3 months earlier in women of higher socio-economic strata. Mazor and Israel  stress the importance of better nutritional status for the earlier onset of menarche.
Singh  has shown the relation between the family size and the age of menarche. There is a definite correlation between the size of the family and the age of menarche. Similar correlation is also found between the number of sisters a girl has and the age of menarche. But Singh  also emphasised the need for further evaluation of these factors.
Sera Israel  found no relation between the rank in family and the age of menarche. This factor was not evaluated in our study.
There was a definite correlation between places of residence at the time of menarche and the menarchal age. Girls staying in villages and taluka places has a higher age of menarche than those from large towns and cities.
We did not find any correlation between the extra-curricular activities, particularly taking part in outdoor games at the time of puberty and the mean age of menarche. There was no correlation between the diet and the age of menarche.
We thank Dr. V. N. Purandare, Head, Department of Obstetric and Gynaeo3 logy, K. E. M. Hospital and Seth G. S. Medical College and Dr. C. K. Deshpande, Dean of the above Institutions for allowing us to publish the hospital data.
[Table 1], [Table 2], [Table 3], [Table 4], [Table 5], [Table 6], [Table 7], [Table 8]