Assessment of energy expenditure in overweight women

PURPOSE

To compare field measures of average daily energy expenditure (ADEE) against criterion data by the doubly labeled water method (DLW) in overweight women.

METHODS

The subject were 20 overweight (BMI 29.9 +a- 3.0 kg.m-2) premenopausal women. Energy expenditure was measured by DLW and by the factorial method (activity diary, two techniques differing by method to obtain resting energy expenditure, REE), heart-rate monitoring (HR, two techniques differing by the FLEX-point to discriminate sedentary and activity HR), accelerometer, and pedometer.

RESULTS

The ADEE(DLW) was 10.26 +a- 1.1 MJ.d-1. The mean bias (ADEE by the alternative minus ADEE(DLW) was smallest for the accelerometer (+ 0.08 +a- 1.63 MJ) and HR-FLEX10 (+ 0.11 +a- 1.67 MJ). The HR-FLEX(0) technique (lower FLEX-point) overestimated ADEE by + 1.18 (+a- 1.97 MJ). However, the random error (SD of bias) was smaller for both factorial techniques (REE measured: -0.48 +2- 0.81 MJ; REE calculated from the WHO equation: -0.22 +2- 0.88 MJ).

CONCLUSION

The results show that simple factorial methods may assess ADEE with small random errors in population with a rather narrow range of physical activity. The accelerometer and HR with the higher FLEX-point have comparable results with smaller bias but larger random error compared with the factorial techniques.

Amenorrhea in ballet dancers in the Netherlands

The prevalence of amenorrhea was studied among 113 professional and student ballet dancers in the Netherlands (mean age 23.3 yr, SD 4.8). Sixty-one dancers not on oral contraceptives were included in the subsequent analyses. Six cases (prevalence 9.8 percent, 95 percent confidence interval: 2.4-17.2) with secondary amenorrhea (< or = 4 cycles per year; previous menstruation > or = 3 months prior to the study; menarche > or = 1 yr prior to the study) were found. Two dancers had primary amenorrhea (no menarche at the age of > or = 16). There was a negative correlation between the age of menarche and the number of menstrual cycles during the 12 months preceding the study (r = -0.46, P = 0.001). Body composition (four-compartment model), amount of dancing (recorded), resting energy expenditure (ventilated hood), dietary intake (recorded), and indices of eating disorders (Eating Disorders Inventory, EDI) were studied in 15 of the dancers, 5 amenorrheic and 10 eumenorrheic. No significant differences were found between the amenorrheic and eumenorrheic dancers. An explanation for the lower prevalence of amenorrhea in ballet dancers in the Netherlands, compared with U.S. dancers, was not obvious. Relatively low EDI scores (25.8, SD 14.5) in a subsample of 24 dancers could indicate less rigid emphasis on leanness and dieting.