Body weight was measured to the nearest 0.1 kg in light indoor clothing without shoes, using a digital scale. Height was measured using same portable stadiometer. A correction of 0.5 kg was made for the weight of the cloths.
BF % was measured using a commercially available digital weight scale incorporating a bioelectric impedance analyzer (HBF-352, Omron Health care Co., Kyoto, Japan). The instrument is portable and easy to use in epidemiological field surveys. BF % was measured to the nearest 0.1 per cent. The digital weight scale includes a hand grip and foot plate, each of which is equipped with two electrodes. The two electrodes between the left and right grip were short-circuited, along with those for the left and right feet. Upon measurement, the study subject stood on the foot plate and gently grasped the two handgrips with arms held straight forward. During the measurement, the instrument records impedance from the hands to the feet, which corresponds to the whole body impedance, by applying an electric alternating current flux of 500 μA at an operating frequency of 50 kHz. Consequently, BF % was calculated from the impedance value and the pre entered personal data. Total body water was predicted from the impedance index (height2/impedance)15–17. From the total body water, the BF % was calculated as 100 × [weight-(total body water)]/weight17. The calculation is done by software program based on algorithm developed and patented by Omron Health Care Co., Kyoto, Japan. Impedance measured and predicted total body water, which is not displayed to user, is automatically fed to algorithm along with pre entered data and the software calculates the body fat%.