Independent and combined association of parity and short pregnancy with obesity and weight change among Indian women ()
1. INTRODUCTION
Obesity as a health problem needs no introduction in the present day context. The task of the day is to identify the risk factors for obesity. Reproductive factors, especially parity, have been found positively associated with weight gain and the onset of obesity in population-based studies [1-4]. In these studies, excess weight gain associated with a single birth has been estimated to be 2 - 3 kg [5,6]. It has been reported that parity affects body fat and BMI [7] and, in a cohort of older women, Bastian et al. [8] found that higher rates of obesity were associated with an increasing number of children regardless of SES and other confounding factors. Women’s weight tends to increase the most during their first pregnancy compared with subsequent pregnancies [9,10]. Smith et al. [5] found that subgroups of women tend to be more vulnerable to weight gain with pregnancy and to risk of becoming overweight.
Grand multiparity is not only considered as a major risk factor for many obstetric and gynecological disorders and maternal deaths, but also for the development of obesity. The extent of this relationship and the pathways leading to the parity-associated weight gain in the different populations are, however, yet to be understood. Even less is known about changes in measures of central adiposity associated with childbearing.
Short pregnancies influence changes in weight and girth. Maternal fat deposition begins early in pregnancy and has been estimated at 1.5 kg by 7 weeks gestation [11]. Therefore, early fat gain may be retained long term even after a short pregnancy. However, previous studies have not evaluated this major confounder. To the best of our knowledge only one study has reported association of short pregnancy with weight change [12].
The influence of obesity on blood pressure was demonstrated in a socio-economically stratified sample by Gupta and Kapoor [13], pointing towards the risk of developing a high load of obesity among the socioeconomically advanced urban Indians thus making them vulnerable to obesity related health risks. Women are also more burdened than men with the undesirable sociopsychological effects of obesity, because the society as a whole favors thinness, especially for women [14,15].
The prevalence of high obesity among Aggarwal Baniya females has been documented [13]. Although effect of various risk factors on obesity has been studied but the effect of reproductive and maternal health on obesity has received less attention. Based on evidence that pregnancy may adversely affect body weight and central adiposity, we explored these relationships further among Aggarwal Baniya women.
2. MATERIALS AND METHODS
2.1. Target Population
The present study was conducted on Aggarwal Baniya women of Delhi, India. Data for the present cross-sectional study was collected by household survey on 307 adult Aggarwal Baniyas women aged 30 - 50 years (mean age: 38.7 ± 4.87 years). All women reported themselves to be vegetarian with majority of them were Housewives/home makers (94.8%). Non-response rate for all the variables of interest was 7.2% in all cases. Final analysis was performed on the basis of 285 women with complete information. Information was collected during household visits using a proforma that included information on anthropometry and reproductive performance.
2.2. Data Collection
Participants were interviewed through structured proforma. Anthropometric measurements inclu-ding height, weight, skinfold thickness, waist and hip circumference were obtained using standardized procedures.
Body weight was measured by using spring balance to the nearest 500 gm, stature with the help of Martin’s Anthropometer to the nearest mm. Waist circumference and hip circumference were measured with a non stretchable flexible steel tape to the nearest mm. Body mass index was calculated as weight divided by height squared (kg/m2), and categorized as normal (≤25.0), overweight (≥25.0 but ≤30.0), and obese (≥30.0) [16]. Abdominal obesity was defined as waist circumference ≥80 centimetres in women [17]. Waist-to-hip ratio was calculated by dividing waist circumference by hip circumference. High waist hip ratio was defined as ≥0.85 in women [17]. Grand mean thickness (GMT) was calculated by adding all skinfold thicknesses taken at different sites divided by number of skinfold sites. Waist to height ratio was calculated as the ratio of waist circumference (cm) to height (cm). High WHtR was defined as ≥0.50 [18].
Measurements were conducted by trained personnel and all instruments were calibrated once weekly. The protocol for the study was reviewed and approved by Ethical Committee of the Department of Anthropology, Faculty of Sciences, University of Delhi, India.
2.3. Statistical Analysis
Parity and short pregnancy were classified as 1 through 3+ based on the self-reported number of live births and short pregnancies. Short pregnancies included abortions, miscarriages and stillbirths. Few women reported parity and short pregnancy of +3; therefore, women with parity and short pregnancy of +3 were clubbed with parity and short pregnancy of three respectively. Women with 1 - 2 live birth and 1 short pregnancy were used as the reference group for parity and short pregnancy respectively. Total pregnancy was defined as combine of live births and short pregnancies. It was classified as 1 through more than 5. Women with more than 5 pregnancies were clubbed together and recoded as group 4.
Data was analysed using Statistical Package for Social Science (SPSS), version 15.0. The results are given as means and standard deviations (SD). ANOVA test was used to compare the measurements between groups. Pearson’s correlation coefficient was used to evaluate the correlations between parity, short pregnancy, total pregnancy and the obesity markers. The question of how parity, short pregnancy and total pregnancy is associated with obesity markers was examined using multiple regression analysis, adjusting for age.
3. RESULTS
Mean weight, height, BMI, waist circumference, waist/ hip ratios, waist/height ratio and grand mean thickness are shown by parity, short pregnancy and total pregnancy groups in Table 1 (Figure 1). The mean value of weight, BMI and other regional obesity indices signifycantly increased with increase in parity and total pregnancy. However, with the increase in number of miscarriage, the mean value of weight, BMI and GMT decreased though regional obesity indices didn’t show any significant association. The number of women with BMI >30 kg/m2 was higher in high parity groups.
Table 2 shows association of obesity markers with parity, short pregnancy and total pregnancy. There were significant positive correlations between parity number, total pregnancy and various obesity markers. However, negative correlations were found between short pregnancies and obesity markers.