The impact of dietary diversity and seasonality in food availability on the quantile distribution of birth size among pregnant women in rural Malawi - a cross-sectional study.

BACKGROUND: Dietary diversity scores can be used as a proxy for dietary intakes and for assessment of nutrient adequacy. Studies from low-resource settings have found maternal dietary diversity scores to be associated with neonatal birth size. We here investigated the relationship between the dietary diversity score among pregnant mothers and birth size of their offspring across quantiles of the birth size variables; birth weight, length, abdominal circumference, and head circumference. We also investigated if seasonality affects birth size across different quantiles. METHODS: Dietary intake and anthropometric data were collected from 190 pregnant women and their neonates in rural Malawi through two agricultural seasons. Dietary data was collected using 24-hour recall interviews and was categorized into the 10-food group dietary diversity score proposed for women by the Food and Agriculture Organization. Neonatal anthropometrics were collected upon delivery at health facilities. Quantile regression analyses were used to investigate associations between dietary diversity scores and birth size, as well as between seasonality and birth size. RESULTS: We found that neonatal abdominal circumference was 0.9 cm larger during the post-harvest season compared to the pre-harvest season among neonates in the 25th quantile. Birth weight was 281.4 g higher for those born during the post-harvest season in the 90th quantile. For a one-unit increase in maternal dietary diversity score, birth weight increased by 56.7 g among those in the 25th quantile and neonatal head circumference increased by 0.2 cm for those in the 70th quantile. However, these findings did not remain significant when considering the cluster effect of the neonatal anthropometric data. CONCLUSIONS: Our findings indicate that the relationship between seasonality and birth size differs across the distribution of birth size. Investigating the effect of seasonality across the distribution of birth size could be important to identify vulnerable subgroups and develop better, targeted interventions to improve maternal and child nutrition and health.

Seasonality in associations between dietary diversity scores and nutrient adequacy ratios among pregnant women in rural Malawi - a cross-sectional study.

BACKGROUND: Dietary diversity scores (DDS) are simple indicators often used as proxies for nutrient adequacy. A 10-food group indicator is proposed by the Food and Agriculture Organization of the United Nations as a global standard for measuring dietary diversity among women in low-resource settings. However, its validity as a proxy for nutrient adequacy across different agricultural seasons for pregnant women has not been determined. OBJECTIVE: We studied associations between DDS and nutrient adequacy ratios (NAR) across two different agricultural seasons (pre- and post-harvest seasons) for pregnant women in rural Malawi and assessed whether a 1-day DDS or a 3-day DDS would be the best indicator of nutrient adequacy. DESIGN: Dietary intakes of 330 pregnant women were assessed between gestational weeks 28 and 35. Intakes of energy, macronutrients, and 11 micronutrients were estimated using three repeated interactive 24-h diet recalls, and DDS were also calculated from these days. Correlation coefficients (r) between DDS, NAR, and mean adequacy ratio (MAR) of the 11 micronutrients were determined. RESULTS: After energy adjustments, we found significant correlations between DDS and MAR with both DDS indicators in the preharvest season (r = 0.22-0.23; p < 0.001) but not in the post-harvest season (p > 0.05). For individual energy-adjusted NARs, correlations were not consistently significant across the two seasons and the two DDS indicators. CONCLUSIONS: Our results suggest that DDS could be used to predict overall nutrient adequacy during the preharvest season. As similar correlations were found using both the 1- and 3-day indicators, we recommend using a 1-day DDS, for simplicity. However, as the indicators are sensitive to seasonality they should be used with care in this study setting.

Maternal dietary intake during pregnancy and its association to birth size in rural Malawi: A cross-sectional study.

In low-resource settings, such as rural Malawi, pregnant women are prone to energy and micronutrient deficiencies with the consequence of delivering low-birth weight infants with higher risks of morbidity and mortality. This study aimed to examine the association between maternal dietary intakes during pregnancy and infant birth size. Dietary intakes of 203 pregnant women were assessed between 28 and 35 weeks of gestation and their infants' (n = 132) birth size measured. Intakes of energy, macronutrients, and 11 micronutrients were estimated using a 3-day interactive 24-hr diet recall. Semiquantitative data on food intakes for four additional days were also collected to assess food patterns. Using multilevel linear regression modeling, maternal intakes of carbohydrate were negatively associated with neonate length (ß: -0.1; 95% CI: -0.2, 0.0 cm/E%) and abdominal circumference (ß: -0.1, 95% CI: -0.2, 0.0 cm/E%), whereas intakes of fat were positively associated with neonate length (ß: 0.1; 95% CI: 0.0, 0.2 cm/E%) and abdominal circumference (ß: 0.1; 95% CI: 0.0, 0.2 cm/E%). Vitamin C intakes were positively associated with birth weight (ß: 1.4; 95% CI: 0.5, 2.3 g/mg). The frequency of milk intake was positively associated with birth weight (ß: 75.3; 95% CI: 13.6, 137.0 g/day). These findings offer practical suggestions for food-based interventions in the study area to promote inclusion of fat, vitamin C-rich foods, and milk in pregnancy.