Total energy expenditure (H218O), physical activity level and milk output of lactating rural Bangladeshi tea workers and nontea workers

Objective: To assess the total daily energy expenditure (TDEE), milk output and physical activity level ( PAL) of chronically malnourished lactating women using the doubly labelled water method (DLW) Design: Prospective, longitudinal study designed to assess the extent of malnutrition and energetics of lactating tea workers and nontea workers Setting: North-east Bangladesh on women working and living in the same tea estates. Subjects: Of an original cohort of 150 lactating women, 30 were selected to participate in this study when they were at about 12 months postpartum. One mother subsequently dropped out. Interventions: On day 1 each women provided a urine sample, was administered a dose of DLW and 6 h later provided another sample. Further urine samples were collected for 21 subsequent days. In addition, every 5 days the mother provided a milk sample and at the same time her baby provided a urine sample. Results: Mean (s.d.) BMI was 17.4 (1.63). Mean TDEE and PAL were significantly higher in workers than nonworkers (8.42 ( 1.38) and 6.83 (2.09) MJ/day, P = 0.02 and 1.92 (0.34) and 1.59 (0.44), P = 0.03, respectively). Mean milk output was similar in the two groups ( 672 ( 180) ml and 749 ( 189) ml in workers and nonworkers, respectively). Conclusions: Based on international BMI cutoffs, 79% of mothers were suffering from some degree of chronic energy deficiency. A total of 35% of workers and 17% of nonworkers were engaged in strenuous physical activity. The mean milk output of both workers and nonworkers was not different and was high especially as most of the mothers were about 12 months postpartum. No relationship was found between menses return and any of the variables studied.