International Journal of Reproductive Research

Abstract

Peak height velocity (PHV) in girls and boys is typically seen at age 11.5 years for girls and 13.5 years for boys. It is a well-known fact that the height of an individual is influenced most (60-80%) by genetics and the rest 40-20% by other environmental factors-nutrition, playing games etc. Growth around the first period can be a wild ride filled with surprises among girls. During puberty, girls go through a lot of changes, and one of the most noticeable changes is height growth. Whether they grow tall or stay petite, health and confidence matter the most. After all, life isn’t measured in centimetres but in memories, experiences, and the joy of being unique for each girl! An average Indian girl can expect to grow about 6-8 centimetres (cms) after they start periods, but some might grow less, while some others could grow even more than 8 cms. That’s why our culture says every girl is unique and embracing each girl’s individual journey is most important.

Genetics is a significant player in the height game. If parents are tall, their daughters might shoot up. A balanced diet rich in Proteins, vitamins &minerals do support healthy growth. Physical activity is critical it keeps girls fit and promotes bone health. Growth spurts usually happen in bursts! A girl might grow several centimetres in just a few months & then stop for a while. Some girls notice a sudden stretch right after their first period, while others may hop on the growth train a bit later.

It’s essential to recognize that not growing as much as peers or seeing friends shoot up, affects emotionally, as girls feel about themselves & lead to comparisons & self-doubt and may be a concern for the parents too!  Engaging in team sports, art, academics build confidence and show that there's more to personal growth than just inches.

Materials & Methods:

This article is based on data of girls and Boys height changes, as a part of a case control and before & after intervention study of adding egg thrice a week to standard mid-day meals. The district of Yadgir in Kalyan Karnataka represented the case of additional intervention and Gadag in neighbouring division as control district. The standard MDM constituted a glass of milk (150-200 ml) in the morning and freshly prepared hot Rice and Sambar around noon. The additional supplement in the schools of Yadgir was a boiled egg or a Banana (for student who didn’t eat eggs) on alternate days. This study was conducted in 30 schools in each district selected following random sampling method and all children of standard 1-8 available on the day/s of visits (at least 3) were covered for interview, clinical examination, and Anthropometric measurements. The investigators were well trained post-graduate scholars in Public Health (MPH), Food and Nutrition (M.Sc. FST), Social work (MSW) & Rural Development of the Karnataka State Rural Development & Panchayat Raj University (KSRDPRU) in Gadag Karnataka. While Height, weight and BMI were observed, for this article the author- the advisor of the study has used only the changes in height over the study period.

Outcomes: The outcomes at end of follow-up for about 100 days indicated that 91% of students consumed MDM regularly (80% of days MDM served) in both districts and in the intervention district 98% consumed eggs, allaying the fears of cultural or traditional barrier. The mean height gain of the girls of class 6,7 & 8 (average age of Menarche), despite a base line negative bias in Yadgir was 1.8, 2.4 and 2 cms as compared to the girls of same standards in Gadag with base line mean advantage 2.2,1.9 & 3 cms, over 100 days. The endline difference of 7.8, 8.6 and 14.4 cms from class 6 to 8 respectively among Gadag girls is attributed to genetic factors only.  What was observed was most girls were confident irrespective of their height or overall body image.

Introduction

Peak height velocity (PHV) in girls and boys is typically seen at age 11.5 years for girls and 13.5 years for boys. The average whole-year PHV is 8.3 cm/y for girls and 9.5 cm/y for boys. While Pubertal growth contributes 17–18% to a boy's final height and 17% to a girl's final height. The age of PHV is calculated using a maturity offset value, which is based on a child's Gender, Date of birth, Date of measurement, standing height, Sitting height and Weight. The ideal age to predict PHV is 9–13 years for girls and 12–16 years for boys. During puberty, girls go through a lot of changes, and one of the most noticeable changes is height growth. It’s fascinating how each girl experiences this growth differently. After their first period, some girls might sprout up like beanstalks, while others might grow just a little bit. This variation in growth can be surprising and often leaves many wonderings, “What’s normal?” [1]. An average Indian girl can expect to grow about 6-8 centimetres (cms) after they start periods, but some might grow less than 6 cms, while others could grow even more than 8 cms.

Factors Influencing Height Growth: i) Genetics- is a significant player in the height game. If parents are tall, their daughters might shoot up ii) Nutrition:  A balanced diet rich in Proteins, vitamins and minerals can support healthy growth iii) Physical Activities:  Regular exercise, team sports, Gymnastics not only keep girls fit but also promote bone health. For Indian Rural girls’ schools are the best opportunities as back home they engaged in household chores and very few families support outdoor sports for girls iv) Hormonal: The hypothalamus controls the pituitary gland, which in turn releases Oestrogen & testosterone important hormones that control growth and drive sexual development and function and play a role in growth. In girls, the concerted actions of oestradiol, Human Growth Hormone HGH /GH) and androstenedione play a role in the pubertal growth spurt, whereas in boys this role is fulfilled by testosterone, GH & oestradiol. Growth spurts usually happen in bursts, so, a girl might grow several centimetres (cms) in just a few months &then stop for a while. There will be ups and downs all along the way among teenagers. Some girls notice a sudden stretch right after their first period, while others may hop on the growth train a bit later [2].

Growth variation in girls can have several impacts. Not growing as much as peers or seeing friends shoot up can affect how girls feel about themselves, leading to comparisons and self-doubt or inferiority complex. Early menarche can lead to sexual violence, especially in rural India, experimenting earlier sexual intercourse, teenage pregnancy with high maternal mortality, sexually transmitted infections, suicidal behaviour, eating disorders, depression and substance use. Early menarche can lead to premature fusion of the growth plates, resulting in a shorter adult height than what was genetically possible. [3].

This article is an attempt to analyse the influence of genetics and better Nutrition (adding egg protein) based on data of Girls and Boys height changes, among class 5,6,8 (aged 12,13 &14) as a part of a case control and before & after intervention study of adding egg thrice a week to standard mid-day meals in Government schools. It looks at the baseline data with genetic advantage or disadvantage in case and control district and increase in height over just 100 days and compares the value add of egg supplementation in bridging the gap.

Data Source & Interpretation – (Mean Height Data only -source: MDMS Study):

Mean height of Yadgir girls studying in lower primary ranged between 115.8±4.6 to 130.7±7.2 in baseline and in end line it improved a bit to 117.4±4.7 to 132.9±7.2, whereas in Gadag it ranged between 111.0±5.1 to 131.4±6.1 in baseline and in end line it showed 112.7±4.9 to 133.9±6.1. The mean height of girls increased about 1.6,0.4,0.6,0.6 and 2.2 cm respectively from Class 1-5. Similarly, in Gadag the girl’s height increased 2.7,2.2,2.3, 2.1 and 2.5 cm from class 1 to 5 over the study period. It is observed that while the girls in Yadgir mean height started with an advantage of 4.8 cm over Gadag girls among class 1 and increased by 14.9 cm over 5 years. On the other hand, Gadag girls started with a disadvantage of 4.8 cm but ended with an advantage of 1 cms by the time they reached 10-11 years. Mean height of Yadgir girls studying in higher primary ranged between 132.0±14.1 to 137.7±14.1 in baseline and in end line ranged between 133.8±13.9 to 137.7±13.8, whereas in Gadag it ranged between 137.6±5.7 to 150.1±7.1 in baseline and in end line it ranged from 139.7±5.7 to 153.3±7.1. It is a known fact that the linear growth is influenced by genetic factors. 60-80% of height changes are determined by genes and the rest 40-20% by diet, environment and physical activities like sports working in farms etc. It is inferred that Gadag children have higher chances of gaining more height as compared to Yadgir students due to genetic factors and this hype in the height influences lower improvement in BMI, among Gadag children.

Table 1: Mean height of the 1-8 Class Girls in Yadgir and Gadag.

Notes: BL-Baseline EL-Endline

The mean height of girls in 1st std (aged 6 years) shows an advantage to Yadgir girls by 5.8 cms, in the beginning of the study, and 4.7 cms in the end of the study. The mean height of 7 years at the beginning of the study was similar and by the end Gadag girls grow taller 1.8 cms. The trend continues to be same in 8th year cohorts, with Yadgir girls just 0.5 cms taller but much higher standard deviation (13.2 as compared to 5.6 in Gadag girls) is more in Yadgir girls. In the 9th year cohorts Yadgir girls mean height is about 1.1 cm more but with standard deviation (SD) more than double. In the 10year both district girls gain hardly 1 -1.5 cm height. In the 11th year Gadag girls add mean height of 8 cms as compared to just 2cms. While the same trend of gaining a mean height of 1.5-2.2 cm is seen in Yadgir girls, a spurt of 3.7 cms in 12th year and another 6 cms gain in 13th year is seen in Gadag girls.

Table 2: Increase in Mean height of girls by age over 100 days of observation

Table 2 – depicts the percentage of increase in height between base line and end line survey. Maximum boosting of the heights over period of100 days in Yadgir was seen in the age group of 6 years, followed by age 9 &12, age 10, 13 and 11. The least spurt was observed in age 7 followed by 8-year cohorts. In the control district of Gadag one saw a maximum gain of 2 cms among 13-year-olds, followed by 1.9 cm in 10-year-olds, 7 & 8yrs old, 9 years old, 11 yrs old, 6 years old and the lease in12 year olds in that order. While the gap between maximum and least gain was 1.51 cms in Yadgir, among 6-year-olds, it was 0.54 cm among 12 years old Gadag girls.

The difference in the mean height of Yadgir girls between 6 years old and 13 years old was 19.9 cms in baseline and the same was 20.3 in the endline a gain of 0.4 cms only. In Gadag this difference was 38.1 cms in base line and 39.9 cms in the end line a gain of 1.8 cm. While the standard deviation in any cohorts was in single digits in Gadag (4.8-6.3), this was in double (4.7-13.9) digits in Yadgir girls in 9, 11–13-year-old girls.

Standard deviation quantifies the amount of variation in a set of data points, it tells us how much the individual data points deviate from the average value. Gadag girls with a smaller standard deviation point to the fact that data points are closely packed together, Yadgir girls with a larger SD indicate a more spread-out heights of the girls.

While one observed appreciable (at least 1cm) spurt in in height 6-year-olds and again 9–13-year-olds in Yadgir, in study period of 100 days. In Gadag District this minimum height gain was seen all age cohorts of 6-13 years. Yadgir girls gained ore height than Gadag girls only in the 6,10-, 12-year cohorts and in other 5 age cohorts Gadag girls outsmarted Yadgir girls.

Table 3:  Mean height of the 1-8 class Girls & Boys in Yadgir

A comparison baseline height of girls with boys indicates that in Yadgir district the mean height of boys and girls in 6 & 7 years was same. In the 8th year the boys mean height was a bit better by 0.7cms. The 9-year cohorts of both genders had same mean height. In the 10-year cohort girls had a significant increase height of 5.5 cms. By the 11th year the mean height of boys not only caught up the gap but also increased by 2 additional cms as boys added almost about 9 cms in this age. In the 12th year girl added 2.2 cms and boys were stagnant & fell short 1.5 cms from the previous age cohorts. In the 13 year the girls added 1.5 cms and boys add 5.4cms. In terms of the height gain over 100 days girls added a height of 1.6cm to 2.4 cms) 1.6 cm in 6th year, in 8th year, 2.3 cms in 9th year, 2.2 cms in 10th year, 1.8 cms in 11 year,2.4 cms in 12th year and 2 cms in 13 year. The ages of 7 & 8 girls added least gain of 0.4cm & 0.6cm respectively. The boys added less than 1 cm in the age cohorts of 7 & 8 and more than 1 cms in all other years. The maximum height gain of 2.2 cm among boys and that among girls of 2.5 cms was seen among 12- year-olds. Thus, it is inferred that in Yadgir both girls and boys grow taller height in their 12th year.

A similar comparison baseline height of girls with boys indicates that in Gadag district the mean height of boys and girls in 6 years cohorts was same. In the 7th to 9th year cohorts the boys mean height was better by 1.0 cms and in 10 year the gap closed to less than 0.5 cm. By 11 year the mean height of girls increased beyond that of boys and by 11th year girls were clearly taller than boys by 1.8 cms. That advantage reduced to 0.5 cm in next year cohorts. But 13-year cohorts boys grew taller than girls by 1 cm.  Looking at the impact of mid-day meal addition over 100 days, it was observed that 13 yrs cohort girls added about 3.1 cms, followed by 2.1 cms, 2.2 cms 2.5 cms, 2.1cms, 2.3cms, 2.2cms and 1.7 cms in the reverse order e.g. 12,11,10,9,8,7 and 6 years cohorts respectively. The maximum height gain of 3.2 cm among boys was seen in 13-year cohorts, followed by 2.9, 2.1, 2.3, 2.3, 2, 1.7 and 2.1 cms in reverse order of 12,11,10,9,8,7 and 6 years cohorts respectively.  and that among girls of 2.5 coms was seen among 12- year- olds. Thus, it is inferred that in Gadag both girls and boys grow taller by more than3 cms in 13th year, boys grow by 2.9 cms even in 12th year as against girls. In the remaining cohort both boys and girls grow by about 2.1 -2.3 cms in the study period. The least growth of height of 1.7 cms was seen in 6th year girl cohorts and 7th year boy’s cohort during the study period.

Comparing the overall height gain in both districts, it is inferred that supplementation of eggs did not impact on the increase in height which is mainly controlled by genetic. Since the duration of observation was just 100 days and each child consumed only about 40 eggs, it may not be enough to compare the impact. Observation for at least one year with about 100 eggs consumption is desirable to a draw any inference on this aspect.

Table 4: Mean height of the 1-8 class Girls & Boys in Gadag.

Discussion

An average Indian School age children are expected to grow about 1-3 cms each year between 6-10 years. Thereafter the girls (11-14 years may grow around 6-8 centimetres (cms) after they start periods, but some might grow less than 6 cms, while others could grow even more than 8 cms. On the other hand, boys grow taller after 13-14 years. That’s why we say every girl is unique!

A prospective longitudinal study of apparently healthy children aged three to 18 years from government and private schools of Krishna district, Andhra Pradesh. Height and weight were measured at baseline and three-monthly intervals for one year (October 2018 to October 2019). Age- and sex-specific height velocity percentiles were generated. The data was available in 1627 boys and 1700 girls. The mean peak height velocity (PHV) was 7.18±2.56 cm in boys observed at 12-12.9 years and 5.8±2.56 cm in girls at 10-10.9 years. This when compared our study matches similar gains over period of 100 days.

Andhra study reported that most girls 925.5%) had their menarche by 12 years in Rural and 23% in Urban areas by 13 years. While 4% of rural area had menarche by 11 years and only 3% of Urban 13 years had menarche. While all urban girls attained menarche by 15 years, 3% of rural girls had it in 16th year. Nutrition plays a role in menarche. The chronology of secondary characteristics development indicated that Girls had Breast buds by 10th year, pubic hair by 11-year, Peak height velocity (PHV) in 12.5 years and Menarche by13th years and adult ovulation from the age of 14 years. On the other hand, among boys around 11.5 years Testes and Penis become active, by 11.5 years pubic hairs start growing. Spermarche is seen around 13.5 years, PHV late 14th year.

Spermarche is the developmental milestone when a male first produces sperm and is considered the male counterpart to menarche in females.

Impact of Growth Variation: Growth variation in girls can have several impacts. Not growing as much as peers or seeing friends shoot up can affect how girls feel about themselves, leading to comparisons and self-doubt or inferiority complex [7]. Girls enter puberty two years earlier than boys and have a slightly lower peak height velocity. Early menarche can lead to experimenting earlier sexual intercourse, teenage pregnancy with high maternal mortality, sexual violence, sexually transmitted infections, suicidal behaviour, eating disorders, depression and substance use. Early menarche can lead to premature fusion of the growth plates, resulting in a shorter adult height than what was genetically possible and may have higher bone mineral density in the lumbar spine and femoral neck later in life. And have a 23% higher risk of developing breast cancer, an increased risk of developing cardiovascular diseases such as hypertension, coronary heart disease, and stroke [3].

Conclusion

Instead of focusing solely on height, it’s vital to celebrate all the talents & strengths that make each girl unique. Engaging in team sports, art, academics build confidence & show that there's more to personal growth than just centimetres. Each girl has her own unique qualities that make her special beyond just height.

Growth after the first period in girls can be a wild ride filled with surprises. What’s most important is embracing each girl’s individual journey. Whether they grow tall or stay petite, remembering that health and confidence matter most is key. After all, life isn’t measured in centimetres but in memories, experiences, and the joy of being unique for each girl.

The mean height gain of the girls of class 6,7 & 8 (12-14 yrs average age of Menarche), despite a base line negative bias in Yadgir was 1.8, 2.4 and 2 cms as compared to the girls of same standards in Gadag with base line mean advantage 2.2,1.9 & 3 cms, over 100 days. The endline difference of 7.8, 8.6 and 14.4 cms from class 6 to 8 respectively among Gadag girls is attributed to genetic factors only.  It proved the well-known fact that the height of an individual is influenced most (60-80%) by genetics and the rest 40-20% only by other factors like nutrition, playing games etc.

The short duration of study is not enough to draw any conclusion on the gain of height due to egg (Protein) supplementation. Observation for at least one year with about 100 eggs consumption is desirable to a draw any inference on this aspect.

The Girls in KSRDPRU Study

First large-scale study from South India evaluating Peak height velocity for children aged 3 to 18 years.

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