Brief Reports Indian Pediatrics 2000;37: 872-876
Socioeconomic and Demographic Factors Associated with Birth Weight: A Community Based Study in Kerala
T. Radhakrishnan K.R. Thankappan R.S. Vasan P.S. Sarma From the Achutha Menon Center for Health Science Studies, Sree Chitra Tirunal Institute for Medical Sciences and Technology, Thiruvananthapuram. Reprint requests: Dr. K.R. Thankappan, Associate Professor, Achutha Menon Center for Health Science Studies, Sree Chitra Tirunal Institute for Medical Sciences and Technology, Thiruvananthapuram 695 011, India. E-mail:
[email protected] Manuscript received: October 5, 1999; Initial review completed: November 26, 1999; Revision accepted: February 15, 2000
The World Health Organization defines low birth weight (LBW) as less than 2500 grams at birth, irrespective of the region, the community or culture. LBW has been associated with a high infant mortality, morbidity in childhood and with an elevated risk of diabetes mellitus, hypertension and other cardiovascular disease in adulthood(1). Kerala State is noted for its high health achievements at low cost; most health indices are comparable to those of developed countries(2). However, Kerala has been reported to have a high proportion of LBW compared to developed countries; the National Family Health Survey of India (1992) reported that 18.2% of newborns in Kerala have a LBW(3). The present investigation was designed to determine the proportion of LBW infants in a community based sample in Kerala and to evaluate potential socioeconomic and demographic correlates of the condition. Subjects and Methods Our sampling frame consisted of non-coastal village Panchayaths of Thiruvanan-thapuram district in Kerala state. We chose this district because of its well functional Integrated Child Development Services (ICDS) Program, a feature that ensures adequacy of birth records of infants born in the district and facilitates tracking of the mothers(4). Kadakampally village Panchayath was selected for the present investigation. We performed a cross sectional survey of all infants born in Kadakampally Panchayath during the reference period from 1 January, 1997 to 31 December, 1997. Based on its population size of 24540(5), and the state-wide birth rate of 17/1000, we estimated that a sample size of about 400 live births would yield reliable estimates of the frequency of LBW and would be adequate to assess the socioeconomic and demographic factors associated with LBW. We contacted the ICDS centers in Kadakampally Panchayath and collected the birth records of all infants born in 1997 and the addresses of their mothers. There were 294 mothers who delivered 301
infants during the reference period. After exclusion of 21 infants (14 twins, 7 others without birth records), 280 infants and their mothers constituted our study sample. Mothers of these 280 infants were contacted by one of the investigators (TR) and informa-tion collected on socioeconomic factors, demographic characteristics, and medical history using a pre tested questionnaire. We collected information regarding the education of the mother and the father of the infant, family income, housing conditions like roof of the house, wall of the house, floor of the house and floor area of the house. Socio-economic status (SES) of the households was assessed as a composite index incorporating several of these variables. Briefly, a weighted score (range 7 to 21, median 13), based on the variables listed above was used to categorize our sample into two groups Low SES below the median and high SES above the median score. Previous studies in Kerala have validated such an approach for determining socioeconomic status of households in Kerala(6). The questionnaire also sought the following additional demo-graphic and medical information: maternal age at delivery, occupation of mother, religion, place of delivery, antenatal care including history of sonographic examination during pregnancy, birth order, gestational age and sex of the baby. Bivariate and multivariate analyses were done on 265 term babies only while other descriptive data analysis was done on all babies (n = 280). Chi square tests and chi square trend test was used to assess bivariate associations of select predictor variables with low birth weight. We constructed multiple logistic regression models to assess the association of SES with the occurrence of a LBW infant adjusting for other predictor variables. A p value 37 weeks, n = 265), 16.2% (95% CI = 11.7-20.7) had a LBW. Among 15 pre-term babies 54% had a LBW. In the bivariate analysis SES of family was found to be significantly associated with LBW (Table I). In multivariate logistic regression model also maternal SES emerged as the principal determinant of LBW. A low SES was associated with a 3.5 fold (95% CI = 1.6-7.6) elevated risk of LBW in the baby compared to a high SES of the mother. There was no association found between LBW and other variables included in the multivariable analyses (Table II ). Table I - Bivariate Associations of Birth-Weight and Selected Characteristics Low birth weight (n = 43)
Normal birth weight (n = 222)
Males
18 (41.8)
114 (51.4)
Females
25 (58.1)
108 (48.6)
Low
30 (69.8)
101 (45.5)
High
13 (30.2)
121 (54.5)
Variable
Chi square p value
Sex of the infant 0.331y
Socio-economic status@
Number of antenatal check-ups
0.006y
