Parallel deficits in linear growth and mental development in low-income Mexican infants in the second year of life.
OBJECTIVE
To explore anthropometric indicators and mental development in very-low-income children in the second year of life.


METHODS
Cross-sectional survey.


METHODS
Low-income areas (income <20th percentile) in semi-urban Mexico (defined as towns or cities with 2,500-50,000 inhabitants).


METHODS
Eight hundred and ninety-six children aged 12.5-23.5 months surveyed from September to December 2001.


METHODS
Questionnaire survey and anthropometric survey of households. Multivariate regression models evaluated differences across age in anthropometry (height-for-age Z-score (HAZ) and weight-for-height Z-score) and cognitive function (Mental Development Index (MDI) of the Bayley Scales of Infant Development) while controlling for socio-economic and parental characteristics.


RESULTS
There was a significant decline in HAZ and in age-adjusted MDI score across the second year of life. Although the children showed MDI scores close to the mean, normed US values at 13-14 months, the scores were significantly lower than expected in older children (P < 0.0001), even after controlling for socio-economic status and parental characteristics. At 13-14 months, only 3% of children received scores below 70 (less than minus two standard deviations), whereas by 19-20 months, almost 17% of children were performing below this level. No socio-economic or parental characteristics were significant predictors of HAZ or MDI.


CONCLUSIONS
Parallel deficits are evident in both height-for-age and cognitive functioning during the second year of life in low-income Mexican infants. The consistency of these growth and development findings further stresses the need for targeted interventions to reduce the vulnerability of low-income Mexican children very early in life.
Fernald
Lia C
LC
School of Public Health, University of California, Berkeley, 140 Warren Hall, 94720-7360, USA. fernald@berkeley.edu
Neufeld
Lynnette M
LM
Barton
Lauren R
LR
Schnaas
Lourdes
L
Rivera
Juan
J
Gertler
Paul J
PJ
D000886:Anthropometry; D001827:Body Height / Q000502:physiology*; D001835:Body Weight / Q000502:physiology; D002657:Child Development; D003071:Cognition / Q000502:physiology*; D003430:Cross-Sectional Studies; D005260:Female; D006128:Growth / Q000502:physiology; D006306:Health Surveys; D006801:Humans; D007223:Infant; D007225:Infant Food / Q000592:standards*; D007228:Infant Nutrition Disorders / Q000453:epidemiology / Q000209:etiology; D007227:Infant Nutritional Physiological Phenomena; D008297:Male; D008800:Mexico / Q000453:epidemiology; D015999:Multivariate Analysis; D011203:Poverty; D012044:Regression Analysis; D012923:Social Class; D014504:Urban Health; D014886:Weaning