A comparison of health and fitness-related variables in a small sample of children of Japanese descent on 2 continents.

OBJECTIVE To compare physical characteristics, health and fitness-related variables, and nutrient intake between children of Japanese ancestry living in the United States and Japan. DESIGN Cross-sectional study. SETTING Miami, Fla, and Tsukuba, Japan. SUBJECTS Fourteen children of Japanese descent living in the United States and 14 sex- and age-matched children living in Japan. MAIN OUTCOME MEASURES US and Japanese resident groups were compared on physical characteristics, health and fitness-related variables, and nutrient intake using the t test for paired samples. To assess differences between groups in variables not statistically significant, effect sizes were calculated using the Cohen d test of standardized differences. RESULTS The following significant differences were found between US and Japanese resident groups, respectively: body mass index, 19.3 and 16.9, P =.02; percentage of body fat, 22.0% and 14.3%, P =.002; diastolic blood pressure, 65.8 and 58.9 mm Hg, P =.01; total cholesterol, 169.8 and 138.7 mg/dL (4.39 and 3.59 mmol/L, P =.001); low-density lipoprotein cholesterol, 108.2 and 88.0 mg/dL (2.80 and 2.28 mmol/L, P =.01); triglycerides, 92.5 and 59.0 mg/dL (1.04 and 0.67 mmol/L, P =.02); percentage of fat intake, 26.1% and 20.3%, P =.001; percentage of saturated fat intake, 7.9% and 6.1%, P<.002; percentage of carbohydrate intake, 57.9% and 63.9% (P =.004); vertical jump, 28.9 and 34.4 cm, P =.02; and flexibility, 58.2 and 42.6 cm, P =.002. Using the Cohen d test, US residents showed a moderately greater systolic blood pressure (107.5 vs 101.9 mm Hg, P =.10) and leg strength (81.5 vs 55.8 kg, P =.11) than did Japanese residents. CONCLUSIONS A small sample (n = 14) of children of Japanese descent living in Florida showed more adverse health-related characteristics than did a comparable group of their peers living in Japan. The results are probably related to differences in their diets. It remains to be seen whether the differences in diets are related to where the children live.