socio-economic group while only 14% of the
urban school girls were of low socio-
economic group. The question of a proper
definition of socio-economic status in
Nigeria however arises, considering that
there is little or no difference in menarchial
age between girls in the middle and high
socio-economic groups. In fact, in one of the
schools studied, we discovered that girls in
the middle class had a lower mean
menarchial age than girls in the high social
class. This clearly is a reflection of the
discrepancy between social class and
earning power in Nigeria today. Most
Business men are placed within the middle
class because of their educational
attainment. They are generally richer and
have more assets and therefore a better
standard of living than the professionals
(the so-called elites) who are classified as the
high social class. This is reflected in the
mean menarchial age of their daughters. It
therefore implies that the classification of
socio-economic status in the developed
world, where educational attainment is
almost concomitant with social well being,
may not be applicable in Nigeria. Therefore,
we suggest a redefinition of socio-economic
status in Nigeria, based on earning power
and assets such as cars and landed property,
which better reflect the standard of living.
In this study there was similarity in the
mean menarchial age of urban school girls
involved in vigorous sports and those not
involved. While in rural area, there was a
significantly higher mean age of menarche
for girls involved in active sports than those
not involved. This corroborates an earlier
report that active sports increase the age of
menarche.9 This may be due to the release of
androgen hormones (aldosterone) in
sporting girls which is likely to delay
menarche. Perhaps the similarity in the
mean menarchial age of the urban school
girls involved in vigorous sporting activity
and those not involved in vigorous sporting
is because most of the urban girls are in high
socio-economic class. They are better
nourished and therefore have a better ability
to cope with the strenuous effect of vigorous
sporting activity on the body physiology.
This may also contribute to the generally
lower mean menarchial age of girls in urban
area.
Conclusions
In conclusion, urban school girls had a
lower mean age of menarche than rural
school girls. Low menarchial age can be a
reflection of high socio-economic status,
while vigorous sports tend to increase
menarchial age. There is need for
redefinition of socio-economic status in
Nigeria.
References
1. Abioye-kuteyi EA, Ojofetimi EO, Anina OI,
Kio F, Aluko Y, Mosuro O. The Influence of
socio-economic and nutritional status on
menarche in Nigeria school girls. Nutri
Health.1997;11:186-95.
2. Dare FO, Oguniyi SO, Makinde OO. Biosocial
Factors affecting Menarche in mixed
Nigerian population. Cent Afri J Med.1992;77-
81
3. Toriola AL, Mathur DN. Mentrual
dysfunction in Nigerian Athlethes. Br J Obstet
Gynaecol 1986;93: 979-85.
4. Samsudin L. The age of menarche as related
to physical growth of junior high school girls
in Jakarta. Paediatr- Indones.1990;30: 254-60.
5. Diegton CM, Sykes H, Walker DT.
Rheumatoid Arthritis, HLA identity and age
of menarche. Ann Rheum- Dis. 1993;52:322-6.
6. Valenzuela C, Avendano A, Hueta J, Wells P,
Gana R. Age of menarche and genetic blood
markers. Rev. Med Chil.1990;118:736-8.'
7. Lin WS, Chen AC, Su JZ, Zhu FC, Xing WH,
Li JY, Ye GS. The menarche of Chinese girls.
An Hum.Biol. 1992;502-12.
8. Ikechebelu JI. The age of menarche in
Nigerian school girls, its relationship to
socio- economic status with comments on the
secular trends. Orient J Med 1991;1:182-5.
9. Stager JM, Hatler LK. Menarche in Athlethes:
The influence of genetic and pre-pubertal
training. Med Sci Sports Exerc.1988;29:269-73.