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.


METHODS
Cross-sectional, institution-based, validity and reliability study.


METHODS
Seven higher secondary schools were covered in the limits of Greater Hyderabad Municipal Corporation, Hyderabad, India.


METHODS
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.
Division of Micronutrient Research, National Institute of Nutrition, Indian Council of Medical Research, Jamai-Osmania, Hyderabad, Andhra Pradesh, India.
Little Flower
LF
Augustine
Shahnaz
S
Vazir
Sylvia
S
Fernandez Rao
M Vishnuvardhana
MV
Rao
A
A
Laxmaiah
P
P
Ravinder
V Vikas
VV
Rao
K Madhavan
KM
Nair
D000293:Adolescent; D001205:Ascorbic Acid / Q000097:blood; D015415:Biomarkers / Q000097:blood; D003430:Cross-Sectional Studies; D005260:Female; D005492:Folic Acid / Q000097:blood; D007722:Health Knowledge, Attitudes, Practice; D006801:Humans; D007194:India; D019266:Iron, Dietary / Q000097:blood; D008297:Male; D018977:Micronutrients / Q000008:administration & dosage* / Q000172:deficiency; D009752:Nutritional Status; D011594:Psychometrics / Q000379:methods*; D012574:Schools; D012959:Socioeconomic Factors; D013334:Students; D011795:Surveys and Questionnaires; D014801:Vitamin A / Q000097:blood; D055815:Young Adult; D024502:alpha-Tocopherol / Q000097:blood
D015415:Biomarkers; D019266:Iron, Dietary; D018977:Micronutrients; D014801:Vitamin A; D005492:Folic Acid; D024502:alpha-Tocopherol; D001205:Ascorbic Acid