Reproducibility and validity of a quantitative food frequency questionnaire in an urban and rural area of northern India.

Background. Food frequency questionnaires (FFQs) have been used in epidemiological studies across the world to capture the usual food intake of individuals. As food habits vary in different population groups, FFQs should be validated before use. Hence, we determined the reproducibility and validity of FFQs designed for urban and rural populations of northern India. Methods. Separate FFQs, designed for urban and rural populations using standard methods, were administered to a sample of 200 subjects (100 urban and 100 rural) in the age group of 35–70 years in the beginning (baseline FFQ) of the study and after an interval of 1 year (1-year FFQ) to assess their reproducibility. Six 24-hour dietary-recalls, taken at an interval of 2 months over a period of 1 year, were used as a reference method to test the validity. Crude and energyadjusted nutrient intakes estimated from FFQs and 24-hour dietary-recalls were compared using Pearson correlation coefficients. Bland and Altman plots were also used to test the agreement between the two methods. Results. Nutrient intakes were found to be similar at the baseline and 1-year FFQs in urban and rural areas. The unadjusted Pearson correlation between 24-hour dietaryrecalls and 1-year FFQ ranged from 0.22 for vitamin C to 0.63 for iron in the urban area. It ranged from 0.06 for vitamin C to 0.74 for energy in the rural area. The correlations lowered after adjusting for energy and there was a minimal increase after de-attenuation. Conclusion. The FFQs were reproducible and valid for assessing nutrient intakes except for some micronutrients.

Perceptions of the intensity of specific physical activities in Bangalore, South India: implications for exercise prescription.

OBJECTIVE: To assess perceptions of the intensity of specific physical activities in urban Indians and to determine whether these perceptions are dependent on age, gender, body mass index and actual physical patterns. METHOD: A self-administered questionnaire in a convenience sample of 782 adults (441 women) aged 17 to 70 years in the city of Bangalore. RESULTS: Women rated the intensity of carpentry, jogging, manual labour and walking uphill significantly higher than men. These differences persisted when they were adjusted for total daily physical activity levels and levels of discretionary exercise. In contrast, while men rated household activities such as manual washing of clothes and sweeping at higher levels than women, these differences disappeared when they were adjusted for actual levels of daily activity related to household chores. There were clear age-related changes in the perception of intensity of physical activities and these persisted even after adjustment for overall physical activity patterns. CONCLUSIONS: This study demonstrates clear age and gender-related differences in the perception of physical activities. This is important to know while motivating individuals to change physical activity patterns and assumes added importance given the recent evidence that perceived intensity of habitual activity is predictive of coronary heart disease, even at levels of activity that are below standard recommendations.

Effect of age and nutritional status on heart rate responses to cough and maximum handgrip.

Autonomic nerve activity can be assessed using simple bed side tests such as cough and maximum hand grip (MHG). The alterations in these tests are, however, poorly documented in physiological states. The present study aimed to uncover the effect of nutritional status and age on these tests. 93 male adults were divided into normal body mass index (BMI) (BMI; 18.5 to 25 kg/m2; young 18-30 yrs, n=28; old >60 yrs, n=25) and low BMI (BMI; <18.5 kg/m2; young 18-30 yrs, n=19; old >60 yrs, n=14) groups. The younger subjects showed a significantly higher heart rate response to cough and MHG in both normal and low BMI groups as compared to the older subjects (P<0.01). However, there were no significant differences for the heart rate responses to cough and MHG between the low and normal BMI groups either in the young or in the elderly. The data suggest that while the heart rate response to cough and MHG are useful tests of vagal activity to the heart when expected differences are large, they may be of limited use in uncovering more subtle changes.

Practices and perceptions of physical activity in urban, employed, middle-class Indians.

The aim of this study was to describe the detailed physical activity profiles of educated, employed, urban Indians and to ascertain their knowledge about the benefits of exercise, their concept of 'ideal' exercise, and the constraints in achieving it. To this end, 401 subjects (193 males, 208 females) between the ages of 25 and 58 years were studied. Women were significantly more active than men (p < 0.05), largely due to enhanced household activity (p < 0.05), which was not offset by the higher leisure time-related exercise of males (p < 0.05). Over 50 percent of subjects were aware of the benefits of exercise in preventing heart disease. The subjects' perceptions of 'ideal' exercise, based on exercise programmes they had drawn up for themselves, were adequate in terms of frequency and duration, but inadequate in intensity, when compared with the current recommendations for exercise in primary prevention of coronary heart disease. Lack of time (men 53.4%, women 68.3%) and lack of motivation (men 26.4%, women 28.4%) were the most-often cited reasons for being unable to achieve 'ideal' exercise goals. The data provides an important framework for understanding physical activity profiles of urban, educated and employed Indians on the basis of which behavioural strategies can be formulated to enhance physical activity and reduce cardiovascular risk.

The development & characteristics of a physical activity questionnaire for epidemiological studies in urban middle class Indians.

A single page physical activity questionnaire was designed for use in epidemiological studies. The questionnaire estimates 24 h energy expenditure as well as components of occupation and discretionary leisure time activities. Estimates of physical activity were highly repeatable, when the questionnaire was re-administered within a 4 wk period (e.g., r = 0.86, P < 0.01 for 24 h energy expenditure). Relative validity was assessed by comparing energy intake (using repeated 24 h dietary recalls) and expenditure (using the physical activity questionnaire) over the same period. A correlate of r = 0.33, P < 0.05 between the two measures compared well with reports from literature. The discriminatory power of the questionnaire was assessed by comparing the physical activity patterns of young (18-30 yr) and older (> 60 yr), free living healthy subjects. The questionnaire provides a tool for the assessment of physical activity patterns of urban middle class Indians, which despite its importance has been inadequately studied so far.

Gender differences in muscle strength & endurance in young Indian adults.

Muscle strength was studied in 70 males and 53 females between the ages of 17-30 yr, using a handgrip dynamometer. In a subset group of 31 males and 20 females, muscle endurance during sustained isometric contraction was studied using a load cell based handgrip dynamometer coupled to a polygraph. The males had a significantly greater muscle mass and lower body fat as compared to the females. Males had close to twice the handgrip strength of females in absolute terms (P < 0.01) and this difference persisted after correction for forearm muscle area (P < 0.05). In contrast, the rate of decline of muscle strength during sustained isometric contraction was lower in females as compared to males (P < 0.05), suggestive of greater skeletal muscle endurance in females. Physical activity patterns were not a determinant of skeletal muscle function. These findings are consistent with gender specific muscle fibre characteristics reported in literature in other racial groups.