Understanding the complex determinants of height and adiposity in disadvantaged daycare preschoolers in Salvador, NE Brazil through structural equation modelling.
BACKGROUND
Earlier we reported on growth and adiposity in a cross-sectional study of disadvantaged Brazilian preschoolers. Here we extend the work on these children, using structural equation modelling (SEM) to gather information on the complex relationships between the variables influencing height and adiposity. We hope this information will help improve the design and effectiveness of future interventions for preschoolers.


METHODS
In 376 preschoolers aged 3-6 years attending seven philanthropic daycares in Salvador, we used SEM to examine direct and indirect relationships among biological (sex, ethnicity, birth order, maternal height and weight), socio-economic, micronutrient (haemoglobin, serum selenium and zinc), and environmental (helminths, de-worming) variables on height and adiposity, as reflected by Z-scores for height-for-age (HAZ) and body mass index (BMIZ).


RESULTS
Of the children, 11 % had HAZ < -1, 15 % had WHZ < -1, and 14 % had BMIZ > 1. Of their mothers, 8 % had short stature, and 50 % were overweight or obese. Based on standardized regression coefficients, significant direct effects (p < 0.05) for HAZ were maternal height (0.39), being white (-0.07), having helminth infection (-0.09), and serum zinc (-0.11). For BMIZ, significant direct effects were maternal weight (0.21), extremely low SES (-0.15), and haemoglobin (0.14). Indirect (p < 0.05) effects for HAZ were sex (being male) (-0.02), helminth infection (-0.01), de-worming treatment (0.01), and serum selenium (-0.02), and for BMIZ were extremely low SES (-0.001), helminth infection (-0.004), and serum selenium (0.02).


CONCLUSIONS
Of the multiple factors influencing preschoolers' growth, helminth infection was a modifiable risk factor directly and indirectly affecting HAZ and BMIZ, respectively. Hence the WHO de-worming recommendation should include preschoolers living in at-risk environments as well as school-aged children.
Department of Human Nutrition, University of Otago, PO Box 56, Dunedin, 9015, New Zealand. Rebecca.Lander@ucdenver.edu.
Rebecca L
RL
Lander
Department of Preventive and Social Medicine, University of Otago, PO Box 56, Dunedin, New Zealand. Sheila.Williams@otago.ac.nz.
Sheila M
SM
Williams
Hospital Universitario Professor Edgard Santos, Fima Lifshitz Research Unit, Salvador, Bahia, Brazil. hugocrj@gmail.com.
Hugo
H
Costa-Ribeiro
Hospital Universitario Professor Edgard Santos, Fima Lifshitz Research Unit, Salvador, Bahia, Brazil. mattosangela@gmail.com.
Angela P
AP
Mattos
Hospital Universitario Professor Edgard Santos, Fima Lifshitz Research Unit, Salvador, Bahia, Brazil. danile_leal@yahoo.com.br.
Danile L
DL
Barreto
Department of Human Nutrition, University of Otago, PO Box 56, Dunedin, 9015, New Zealand. Lisa.Houghton@otago.ac.nz.
Lisa A
LA
Houghton
Department of Human Nutrition, University of Otago, PO Box 56, Dunedin, 9015, New Zealand. Karl.Bailey@otago.ac.nz.
Karl B
KB
Bailey
Department of Human Nutrition, University of Otago, PO Box 56, Dunedin, 9015, New Zealand. alastair.lander@gmail.com.
Alastair G
AG
Lander
Department of Human Nutrition, University of Otago, PO Box 56, Dunedin, 9015, New Zealand. Rosalind.Gibson@otago.ac.nz.
Rosalind S
RS
Gibson
D050154:Adiposity; D000818:Animals; D001827:Body Height; D015992:Body Mass Index; D001938:Brazil / Q000453:epidemiology; D002648:Child; D002675:Child, Preschool; D003430:Cross-Sectional Studies; D004777:Environment; D005006:Ethnicity; D005260:Female; D006130:Growth Disorders / Q000097:blood / Q000453:epidemiology / Q000209:etiology*; D006376:Helminths; D006454:Hemoglobins / Q000378:metabolism; D006801:Humans; D008297:Male; D009035:Mothers; D009765:Obesity / Q000097:blood / Q000453:epidemiology / Q000209:etiology*; D050177:Overweight; D012307:Risk Factors; D012923:Social Class; D014131:Trace Elements / Q000097:blood; D035862:Vulnerable Populations
D006454:Hemoglobins; D014131:Trace Elements