Poster Topical Area: Maternal, Perinatal and Pediatric Nutrition
Location: Hall D
Poster Board Number: 347
Objective: To determine the association between hydration status measured from urinary osmometry and bioelectrical impedance analysis (BIA) in urban lactating women in the Western Highlands of Guatemala.
Methods: 40 lactating women with infants between 37-194 days of age from the urban area of Quetzaltenango, Guatemala, were recruited to participate in this study by convenience sampling. Participation was voluntary with written consent. Participants were asked to collect their urine samples on site. Weigh, height and waist circumference were measured by trained anthropometrists using a SECA® equipment. BIA was conducted using the Medical Body Composition Analyzer SECA® 525. Total body water (TBW) and fat free mass (FFM) were calculated by the Analyzer. The urine sample aliquots were prepared and frozen in a -20°C freezer. All 40 urine sample aliquots were defrosted at the final phase of the project and urine osmolality (Uosm) was tested using a Vogel-Löser® model 815. Linear regression was used to test the association between Uosm and FFM/TBW% values. Pearson Chi-square test was used to determine the differences in hydration status categorization of the two measurements. Stata® was used for statistical analysis.
Results: The participants had an average age of 24.9 years old (range: 17-37 y). Levels of schooling were self-reported and there were 4 women with post-secondary education and 36 others with primary or secondary. The mean TBW/FFM% was 73.9% (SD±0.9). The mean Uosm was 599 mOsm/kg (SD±228). There was no linear association between Uosm and TBW/FFM% (p=0.21). When 90 – 900 mOsm Uosm cutoff was used, 4 participants were classified as hypohydrated and 1 hyperhydrated. Using 700 mOsm cutoff, 16 women were in hypohydration category. For BIA, there were 3 women categorized as hypohydration with cutoff of TBW/FFM%<73.2%. There was no statistically significant difference at the frequency level on categorization of the two measurements if using 90 – 900 mOsm cutoff (p=0.50), but only 1 woman were co-classified as hypohydrated by both methods.
Conclusion: At the individual level, the values of Uosm and TBW/FFM% from BIA were poorly related; however, their respective categorization of low hydration status prevalence yielded similar results in lactating women.
Tufts University School of Medicine