Menarcheal Age and Nutritional Status of Secondary School Adolescent Girls in Nnewi, South-East Nigeria

Background: Menarche is an important indicator of pubertal development in adolescent girl. Age at menarche has declined over the years attributable to many factors. Objective: To determine the age at menarche of secondary school adolescent girls and its relationship with anthropometric values, nutritional status, social class of parents, and category of school. Subjects and Methods: Cross-sectional study of 311 secondary school adolescent girls (10 19 years) from two secondary schools (boarding schoolMaria Regina secondary school Nnewi and Anglican Girls Secondary School Nnewi-day school) in Nnewi North LGA of Anambra State, Southeastern Nigeria, between May and June 2018. Semi-structured questionnaires were used to extract their data on sociodemographic characteristics and age at menarche. Height and weight were measured using WHO recommended methods. Body mass index (BMI) was determined using the Quetelet index (kg/m). The relationship between menarche and anthropometric measurement was determined. Results: Of the 313 participants, 212 (68.2%) were post menarcheal, while 99 (31.8%) were pre-menarcheal. The mean age at menarche was 12.79 ± 1.20 years. Early menarcheal age was associated with significantly higher anthropometric values and BMI. Boarding-students had significantly lower menarcheal age (12.69 ± 1.26) compared to the day students (12.86 ± 1.15); students with parents of the high social class had lower menarcheal age (12.56 ± 1.51), compared to those with parents of low social class (12.90 ± 1.05). Conclusion: There was a significant relationship between age at menarche and the nutritional status of the participants. Students with parents of high social class and those in boarding houses had a relatively lower age at menarche. Adequate attention should be given to the nutrition of premenarcheal school girls and those of parents with low social class. Boarding school authorities should ensure measures to alleviate stress amongst boarding-school students. How to cite this paper: Adinma, J.I.B., Egeonu, R.O., Adinma-Obijulu, N.D. and Emeka, E.A. (2021) Menarcheal Age and Nutritional Status of Secondary School Adolescent Girls in Nnewi, South-East Nigeria. Advances in Reproductive Sciences, 9, 139148. https://doi.org/10.4236/arsci.2021.92014 Received: January 14, 2021 Accepted: May 22, 2021 Published: May 25, 2021 Copyright © 2021 by author(s) and Scientific Research Publishing Inc. This work is licensed under the Creative Commons Attribution International License (CC BY 4.0). http://creativecommons.org/licenses/by/4.0/ Open Access J. I. B. Adinma et al. DOI: 10.4236/arsci.2021.92014 140 Advances in Reproductive Sciences


Introduction
Menarche, the first menstrual period is a landmark indicator of puberty, and the age at which girls attain menarche has shown variation across the globe [1]. The average age at menarche has been on the decrease, and this is attributed to several factors such as nutritional status, genetic, environmental conditions, socioeconomic status, and education [2]. Notable among the above factors is the nutritional status. Girls with poor nutritional status have been shown to have delayed menarche compared to those that have good nutritional status [3]. The amount of body fat needed for menses to occur is about 17% of the total body weight at menarche [4]. It is believed that girls with good nutrition tend to achieve this minimum percentage of body fat, and hence, earlier menarcheal age.
The age of menarche varies globally. For instance, the age at menarche in England is 13.1 years while that in the Burundi tribe in Papua New Guinea is 18.8 years [5]. In Indonesia, menarcheal age is 13 years [6]. Carnelo et al., in a systematic review, reported age at menarche in a USA population to be 12 years [7]. In Nigeria, the average age at menarche varies from one geopolitical zone to another [8]- [13]. For example, In Port Harcourt, the average age at menarche has been reported by Okagua et al. to be 12.45 ± 1.24 yrs [8], while in Benin City it is 12.3 yrs [10]. However, Tunauet al. [12] reported a higher age at menarche of 15.26 yrs among school girls in Sokoto, Nigeria.
Nutrition plays a vital role in several aspects of the development of womenduring the adolescence, pre-pregnancy, pregnancy, and postpartum period, and has constituted a major policy thrust in several nations of the world, including Nigeria [14] [15] [16] [17]. Nutritional concern has also constituted the basis for several studies related to macro-and micro-nutrients and the need for their supplementation especially in pregnant women [18] [19] [20].
Reports have shown that girls who have higher BMI are likely to attain menarche earlier than their premenarcheal peers, indicating the relationship between nutritional status and menarche [11] [13] [21]. This study has been undertaken to determine the relationship between menarcheal age and anthropometric indices among secondary school adolescent girls in Nnewi, Southeastern Nigeria. It also elicits the relationship if any between the age at menarche and the social class of the parents of the students together with the pattern of their schooling system i.e. whether boarding or day students.

Subjects and Methods
This was a cross-sectional study, conducted among 311 secondary school ado-Advances in Reproductive Sciences lescent girls (10 -19 years) from two secondary schools (one boarding school and one day school) in Nnewi North LGA of Anambra State of south-eastern Nigeria between May and June 2018. Nnewi North LGA is one of the 21 local government areas of Anambra state. It is located in the southern senatorial zone of Anambra State, and comprises Nnewi urban town and the adjoin Ichi rural community. The city spans over 2789 km square [22] and is mainly inhabited by traders with few civil servants and artisans.
Sample Size and Sampling Technique: The sample size will be determined as per standard method recommended by the WHO Expert Committee (1995) [23] for studies involving nutritional status.
The sample will be calculated using a power calculation (Cole 1997) [24].
where, Z = z value (example 1.96 for 95% confidence interval), P = percentage adolescent girls assumed having poor nutritional status. P will be taken to be where applicable such as the mean menarcheal age and mean nutrient intake as well as inferential statistics like the f-test. P-values of less than 0.05 at 95% confidence interval, was statistically significant.

Results
Of

Discussion
The mean menarcheal age of the students in this study is 12.79 ± 1.20 years. This is similar to menarcheal ages of 13.43 and 12.3 ± 1.18 years reported respectively by Okagua et al. [8] in Port-Harcourt and Osemwenkha et al. [9] in Benin City both in south-southern Nigeria. Similar observation has also been reported for different parts of Nigeria [10] [11] and also by Gumanga et al. [21] (12.50 ± 1.28) in Accra Ghana and Chumlea et al. (12.06 -12.16 yrs) in USA [26]. The menarcheal age observed in this study is however lower than 15.26 years reported by Tunau et al. [12] from Sokoto, Northwestern Nigeria. It is similarly lower than 15 years reported by Umeora et al. [27] from Abakiliki, Southeastern Nigeria the same area as the present study. This apparent disparity in menarcheal age observed from studies carried out among the women from the same ethnic group as exemplified in our present study, and Umeora et al.'s study is not clear, however, it is pertinent to note that Umeora et al.'s study was conducted 12 years ago amongst rural women of reproductive age between 15 and 49 years many of whom may not accurately recall their ages at menarche, in contradiction to the present study which has been conducted only recently, and amongst adolescent girls (10 -19 years) with a higher likelihood of a more accurate recollection of their age at menarche.  [29]. Adolescents with parents of high social class are more likely to be of better nutritional status than those with parents of low social class. In contrast to the above observation, however, Braithwaite et al. [32] had reported that white girls of high social class were protected from early menarche while black girls, irrespective of their social class were not. This suggests that other factors such as race, stress, and environment may be playing a role in the age at menarche.
This study shows that the age at menarche was lower in the boarding-school girls than that of the day-school students. In Nigeria, being a boarding-school student is more expensive to the parents or guardian than being a day student-this indirectly points at the social class of the parents. The disparity in menarcheal age between the boarding and day students may therefore not be unrelated to the likelihood of boarding-school girls being of parents of high social class compared to the day-students whose parents are likely to be of lower social class. In addition, the likelihood of more stress usually experienced by the boarding-school students compared to the day students may constitute a trigger to earlier menarche amongst them [33].
This study has some limitations. The sample size was small and also a schoolbased study. The finding of this study may not be appropriate for generalization as out-of-school adolescent girls were not included in the study. A more encompassing study involving all the segments of adolescent girls vis-à-vis in-school and out-of-school girls is recommended.

Conclusion
This study shows that the mean age at menarche amongst the adolescent secondary school girls was 12.79 ± 1.2 years. There was a significant relationship between age at menarche and the nutritional status of the participants. Students Advances in Reproductive Sciences with parents of high social class and those in boarding houses had a relatively lower age at menarche. Adequate attention should be given to the nutrition of premenarcheal school girls and those of parents with low social class. Boarding school authorities should ensure measures to alleviate stress amongst boarding-school students.