A total 914 pregnant women were identified, from whom 452 newborns were recruited. Non-recruitment was due mainly women following the traditional practice of going to their mothers’ homes for 3 months after delivery. These women did not differ significantly from those recruited in terms of socio-economic status, age of the mother, birth weight and gender of the child. Baseline characteristics of the cohort are given in . The mean (SD) birth weight of 441 children was 2.92 (0.43) kg, with 223 males having a mean (SD) of 2.95 (0.42) kg and 218 females, 2.89 (0.43) kg, with 11 children born at home with no birth weight recorded.
Baseline characteristics of the study households and infants in a birth cohort of 452 children in South India
Of 43 061 home visits during the first year of life, infants were not at home for 1031 (2.4%) visits and information was collected either by proxy or with a recall of >3 days during 1784 (4.1%) visits. The median (range) interval between two home visits was 3 (3-4) days. Breast feeding commenced in 445 children and the Kaplan-Meier estimate of median duration of breast feeding was 17.0 months (interquartile range (IQR) 11.3-22.4 months), with the median age at weaning being 3.0 months (IQR 1.9-4.0 months).
A total of 391 children had complete follow-up for their first year of life, and of these only one had no episodes of morbidity. For these 391 children, the median (IQR) days spent ill per infant were 73 (42-112).
Respiratory illnesses were the most common morbidity, at a rate (95% CI) of 7.4 (6.9 to 7.9) per child-year. Of these, 6.0% were attributable to lower respiratory infection, an incidence rate per child-year of 0.4 (95% CI 0.3 to 0.7). Of the upper respiratory tract illnesses, 618 (30%) were cough/runny nose with fever and 1100 (68%) of those without fever lasted only for a week or less. Gastrointestinal illnesses were the next most common (). An infant spent a median (IQR) of 8 (3-18) days of illness per child-year with gastrointestinal illness and 43 (15-82) days with respiratory illness. Other infections and undifferentiated fever accounted for 17.4% of all episodes.
Summary of all morbidities during the first year of life among a birth cohort of 452 infants in South India
In Poisson regression models fitted for overall morbidity, gastrointestinal and respiratory illnesses, age (3-5 months), masculine gender and family involvement with beedi work were independently associated with increased risk, after adjustment for other baseline characteristics such as birth weight, socio-economic status, household size, etc (tables and ). There was increased risk of respiratory illnesses in the cold/wet season and of gastrointestinal illnesses in the hot/dry season (). Infants exclusively breastfed for at least 4 months had a 15% lower risk of respiratory illnesses ().
Factors associated with episodes of overall morbidity in univariate and multivariate analyses of longitudinal data from 452 infants in South India
Factors associated with gastrointestinal and respiratory illnesses in univariate and multivariate analyses in 452 infants in South India
There were 207 cases of non-infectious morbidities, including injuries (45), anaemia (1), congenital disease (3), convulsions (6), neonatal jaundice (13), birth related morbidities (5), loss of appetite (52), malnutrition (43) and others (39). The incidence rate of non-infectious morbidities was 0.52 (IQR 0.43-0.64) per child-year and the incidence rate of injury-related illness was 0.12 (IQR 0.07-0.19) per child-year.
A total of 3370 hospital visits were made for 2525 episodes of illness and the most common diagnoses were acute respiratory infections (1593, 47.3%), diarrhoea (889, 26.4%), ear infections (309, 9.2%) and fever (165, 4.9%) (). There were a total of 106 hospitalisations, a rate of 28 (IQR 22-35) per 100 child-years. Lower respiratory tract infections and diarrhoea accounted for the majority of admissions.
Rates and causes of outpatient visits and hospital admissions during infancy for 452 infants in South India
It seems that treatment was sought more frequently for boys (1388/2580 episodes, 53.8%) than for girls (1137/2257 episodes, 50.4%) (Wald test, p = 0.12). There was a slightly higher proportion of health care seeking for male children, even among educated mothers and households of higher socio-economic status (individual data not shown). Interestingly, despite more morbidity in boys, girls were hospitalised on more occasions (49, 2.5%) than boys (57, 1.9%).
There were four deaths. One girl child died in hospital due to a congenital cardiopulmonary disorder at 6 months. Three other deaths (two girls, one boy) were due to diarrhoea at 1, 4 and 7 months of age. Two deaths occurred at home, while the third happened at a traditional place of healing. Thus the infant mortality rate (95% CI) for this cohort was 19.9 (9.1 to 37.5) per 1000 live births, when the neonatal mortality rate of 9.9/1000 live births among the women identified for recruitment was included.