Psychometric validation of a knowledge questionnaire on micronutrients among adolescents and its relationship to micronutrient status of 15-19-year-old adolescent boys, Hyderabad, India.

OBJECTIVE: To develop a psychometrically valid questionnaire for testing knowledge on micronutrients and to assess the relationship between knowledge and biomarkers of micronutrient status among adolescents. DESIGN: Cross-sectional, institution-based, validity and reliability study. SETTING: Seven higher secondary schools were covered in the limits of Greater Hyderabad Municipal Corporation, Hyderabad, India. SUBJECTS: Students aged 15-19 years, n 92 for the pre-test, n 108 for test-retest and n 109 for studying the relationship between knowledge and biomarkers of Fe, retinol, ascorbic acid, α-tocopherol, folic acid and vitamin B12 status. RESULTS: From an item pool of 106, thirty-one items were selected based on content validity. Statistical tools to obtain a valid and reliable questionnaire among adolescent boys and girls resulted in eighteen items with a difficulty index of 0·11-0·86, discrimination index of 0·20-0·72 and validity index (point bi-serial correlation) of 0·10-0·62. Reliability as measured by Cronbach's α was 0·71 and the intra-class correlation coefficient was 0·80. A Bland-Altman plot showed good agreement between test and retest scores. The mean response score to the eighteen-item questionnaire was 5·2 (sd 2·68). The mean values of serum retinol were significantly different (P = 0·022) between groups below (24·8 (sd 6·64) µg/dl) and above (28·0 (sd 7·67) µg/dl) the 50th percentile of knowledge score. The relationship persisted after controlling for economic status as a covariate using analysis of covariance (P = 0·018). Other micronutrients did not show any significant relationship. CONCLUSIONS: A valid and reliable eighteen-item knowledge questionnaire was constructed and found to have a significant positive relationship with plasma retinol status alone.

Prevalence of vitamin A deficiency and its determinants among the rural pre-school children of Madhya Pradesh, India.

BACKGROUND: Vitamin A deficiency (VAD) continues to be a major public health nutritional problem in India, even though the National Vitamin A Prophylaxis Programme has been in operation for more than three decades. AIM: To assess the prevalence of vitamin A deficiency among rural pre-school children. SUBJECTS AND METHODS: A community-based cross-sectional study was carried out in rural Madhya Pradesh. A total of 8777 pre-school children were clinically examined for VAD and blood vitamin A levels were estimated in a sub-sample by dried blood spot method. RESULTS: Prevalence of night blindness and Bitot's spot, an objective sign of VAD, was 0.8% and 1.4%, respectively, and prevalence increased significantly (p < 0.001) with age. The proportion of children with blood vitamin A deficiency ( < 20 µg/dL) was 88% (95% CI: 84.8-91.2).The prevalence of Bitot's spot was significantly (p < 0.001) higher among children of lower socio-economic communities, 3-5-year age group and those of illiterate mothers. CONCLUSIONS: VAD is a major public health problem among rural children of Madhya Pradesh. Children of 3-5 years and those belonging to lower socio-economic communities are at high risk of VAD. Therefore, appropriate intervention measures are to be initiated to improve the vitamin A status of children.