Background: Prevalence of child undernutrition is a major public health problem in India. Thinness (low BMI-for-age) is an important anthropometric measure of undernutrition.

Aims and Objectives: The objectives of the present study were to determine age-sex specific prevalence of thinness and its association with socio-economic and demographic variables among rural children of West Bengal, India.

Material and Methods: The present cross-sectional study was carried out among 1250 (618 boys; 632 girls) rural children aged 5 to12 years of Darjeeling, West Bengal. Height and weight were collected using standard anthropometric procedures and Body mass index (BMI) was calculated using standard formula. The prevalence of thinness was assessed by using recently proposed age-sex specific international reference. The data were analyzed using chi-square (χ2) analysis, ANOVA and binary logistic regression in SPSS (version 17.0).

Results: Overall prevalence of thinness among the children was 57.36% (boys: 65.53%; girls: 47.94%; p<0.05). Age-specific prevalence of thinness was observed to be higher in 12 years age-group 82.86% (in boys) and 57.58% (in girls). Binary logistic regression analysis showed that e.g., family size, number of individuals, number of sibs, birth order, fathers occupation, mothers occupation, monthly income and toilet facility were significantly associated with prevalence of thinness among the children (p<0.05).

Conclusion: The prevalence of greater degree of thinness among these children indicates nutritional deprivation. Proper intervention programmes and dissemination of nutrition knowledge are needed. Socio-economic improvement is also necessary to ameliorate the nutrition situation of the children.