Jul 17, 2014 - Indian-adapted Kuppuswamy's socioeconomic status scale. (see Kumar et al., 2012) was used in this study (Table 2). On the basis of scores, ...
AMERICAN JOURNAL OF HUMAN BIOLOGY 26:784–795 (2014)
Original Research Article
Evidence of Inbreeding Depression on Height, Weight, and Body Mass Index: A Population-Based Child Cohort Study MOHD FAREED AND MOHAMMAD AFZAL* Human Genetics and Toxicology Laboratory, Section of Genetics, Department of Zoology, Faculty of Life Sciences, Aligarh Muslim University, Aligarh, 202002, Uttar Pradesh, India
Objective: The study was aimed to estimate the effect of inbreeding on height, weight, and body mass index (BMI) in comparison with non-inbred children. Methods: A cohort study was conducted during April 2013 through July 2013 in Jammu (North India) and a total of 1,270 children (5–15 years of age) were selected in a random way both from inbred and non-inbred families of five Muslim populations. The height and weight was measured using standard methods and the BMI categories were employed as adapted by World Health Organization (WHO). Family pedigrees were drawn to access the family history and children’s inbred status in terms of coefficient of inbreeding (F). Results: Children of inbred families showed decline in mean value for height, weight, and BMI (P < 0.0001). The mean difference (95% confidence interval) in height 27.318 (5.827–8.809), weight 26.590 (5.100–8.081) and BMI 22.133 (0.6419–3.624) for inbred as compared with non-inbred children were found to be significant (P < 0.001). We observed an increase in the difference in mean values for height, weight and BMI with the increase of inbreeding coefficient and these were statistically significant (P < 0.05, using post hoc tests). The frequency of underweight children was found to be higher among individuals in the inbred category (first cousin once removed (F 5 0.03125) >second cousin (F 5 0.0156). In non-consanguineous families or the distant marriages, the coefficient of inbreeding is effectively zero (F 5 0.000). Study variables Standing height was measured twice without shoes to the nearest 0.1 cm using a portable stadiometer (Bio Plus stature meter 2M, Bharat enterprises, Delhi). The weight of the subject was measured twice to the nearest 0.1 kg
TABLE 1. Details of sample size and categories in the study selection Factors Residence
Categories
Rural Urban SES High Medium Low Population Gujjar and Bakarwal Mughal Malik Syed Khan Age (in yrs) 5 6 7 8 9 10 11 12 13 14 15 Gender Male Female
Non-inbred
Inbred
Total (n)
579 (55.67%) 152 (66.09%) 139 (63.47%) 432 (58.62%) 160 (50.96%) 171 (61.51%) 155 (58.71%) 142 (52.98%) 115 (53.99%) 148 (59.92%) 55 (48.25%) 69 (59.48%) 62 (62.63%) 77 (57.46%) 54 (51.43%) 77 (61.11%) 71 (59.17%) 71 (48.63%) 56 (56.57%) 70 (67.31%) 69 (64.49%) 334 (57.99%) 397 (57.21%)
461 (44.33%) 78 (33.91%) 80 (36.53%) 305 (41.38%) 154 (49.04%) 107 (38.49%) 109 (41.29%) 126 (47.02%) 98 (46.01%) 99 (40.08%) 59 (51.75%) 47 (40.52%) 37(37.37%) 57 (42.54%) 51 (48.57%) 49 (38.89%) 49 (40.83%) 75 (51.37%) 43 (43.43%) 34 (32.69%) 38 (35.51%) 242 (42.01%) 297 (42.79%)
1,040 230 219 737 314 278 264 268 213 247 114 116 99 134 105 126 120 146 99 104 107 576 694
Values shown in table indicate number (%) for children. Total sample size 5 1,270; n 5 number of subjects.
American Journal of Human Biology
786
M. FAREED AND M. AFZAL TABLE 2. Socioeconomic status scale (SES) used in the study
Education Profession or honours Graduate or post graduate Intermediate or post high school High school certificate Middle school certificate Primary school certificate Illiterate
Score
Occupation
Score
Income
Score
07 06 05 04 03 02 01
Profession Semi-profession Clerical, shop-owner, farmer Skilled worker Semi-skilled worker Unskilled worker Unemployed
10 06 05 04 03 02 01
30,375 15,188–30,374 11,362–15,187 7,594–11,361 4,556–7,593 1,521–4,555 1,520
12 10 06 04 03 02 01
using weighing machine (Dr Trust, Nectar Lifesciences Ltd., India) with light clothing and without shoes. The mean of the two measurements was used for analysis. BMI categories employed the criteria set forth by World Health Organization (WHO): less than 18.5 kg/m2 5 underweight; 18.5–24.9 kg/m2 5 normal weight; 25.0– 29.9 kg/m2 5 overweight; and 30.0 kg/m2 or more 5 obese. In our study no obese children were found. Parental background characteristics were assessed in two dimensions: the residence (rural or urban) and the socioeconomic status (SES; low, medium and high). The Indian-adapted Kuppuswamy’s socioeconomic status scale (see Kumar et al., 2012) was used in this study (Table 2). On the basis of scores, we categorised SES into three classes: 26–29 5 high, 11–25 5 medium, and SES > age), height-BMI (population > residence > age > gender > SES > inbreeding) and weight-BMI (age > inbreeding > SES > population > gender > residence). The r-value for combined stands for the total number of individuals. Combined results showing the r-value in the order of height-weight > weight-BMI > height-BMI, suggesting that height-weight correlation is more significant as compared with height-BMI, whereas weight-BMI also shows good correlation. †The lowest value is less than zero (i.e., –0.008). The r-value >0.250 is significant at the 0.01 level (twotailed). The r-value between 0.160 and 0.250 are significant at the 0.05 level (two-tailed). The r-values
