An assessment of caloric intake as an indicator of physical activity

Factors Associated with Age-Related Declines in Cardiorespiratory Fitness from Early Adulthood Through Midlife: CARDIA

PURPOSE

This study aimed to describe maximal and submaximal cardiorespiratory fitness from early adulthood to midlife and examine differences in maximal fitness at age 20 yr and changes in fitness overtime by subcategories of sociodemographic, behavioral, and health-related factors.

METHODS

Data include 5018 Coronary Artery Risk Development in Young Adults participants (mean (SD) age, 24.8 (3.7) yr; 53.3% female; and 51.4% Black participants) who completed at least one maximal graded exercise test at baseline and/or the year 7 and 20 exams. Maximal and submaximal fitness were estimated by exercise duration and heart rate at the end of stage 2. Multivariable adjusted linear-mixed models were used to estimate fitness trajectories using age as the mechanism for time after adjustment for covariates. Fitness trajectories from ages 20 to 50 yr in 5-yr increments were estimated overall and by subgroups determined by each factor after adjustment for duration within the less favorable category.

RESULTS

Mean (95% confidence interval) maximal fitness at age 20 and 50 yr was 613 (607-616) and 357 (350-362) s; submaximal heart rate during this period also reflected age-related fitness declines (126 (125-127) and 138 (137-138) bpm). Compared with men, women had lower maximal fitness at age 20 yr (P < 0.001), which persisted over follow-up (P < 0.001); differences were also found by race within sex strata (all P < 0.001). Differences in maximal fitness at age 20 yr were noted by socioeconomic, behavioral, and health-related status in young adulthood (all P < 0.05), which persisted over follow-up (all P < 0.001) and were generally consistent in sex-stratified analyses.

CONCLUSIONS

Targeting individuals experiencing accelerated fitness declines with tailored intervention strategies may provide an opportunity to preserve fitness throughout midlife to reduce lifetime cardiovascular disease risk.

Gender differences in predictors of body weight and body weight change in healthy adults

BACKGROUND

Overweight and obesity are important predictors of a wide variety of health problems. Analysis of naturally occurring changes in body weight can provide valuable insights in improving our understanding of the influence of demographic, lifestyle, and psychosocial factors on weight gain in middle-age adults.

OBJECTIVE

To identify gender-specific predictors of body weight using cross-sectional and longitudinal analyses.

METHODS AND PROCEDURES

Anthropometric, lifestyle and psychosocial factors were measured at baseline and then quarterly for 1 year in 572 healthy adult volunteers from Central Massachusetts who were recruited between 1994 and 1998. Linear mixed models were used to analyze the relationship between body weight and potential predictors, including demographic (e.g., age, educational level), lifestyle (e.g., diet, physical activity, smoking), and psychosocial (e.g., anxiety, depression) factors.

RESULTS

Over the 1-year study period, on average, men gained 0.3 kg and women lost 0.2 kg. Predictors of lower body weight at baseline in both men and women included current cigarette smoking, greater leisure-time physical activity, and lower depression and anxiety scores. Lower body weights were associated with a lower percentage of caloric intake from protein and greater occupational physical activity levels only among men; and with higher education level only among women. Longitudinal predictors of 1-year weight gain among women included increased total caloric intake and decreased leisure-time physical activity, and among men, greater anxiety scores.

DISCUSSION

Demographic, lifestyle and psychosocial factors are independently related to naturally occurring changes in body weight and have marked differential gender effects. These effects should be taken into consideration when designing interventions for weight-loss and maintenance at the individual and population levels.

Comparison of energy expenditure estimates from doubly labeled water, a physical activity questionnaire, and physical activity records

BACKGROUND

Various methods are used by epidemiologists to estimate the energy cost of physical activity; these include physical activity records and recalls. However, there is limited validation of these methods against the doubly labeled water technique for determining energy expenditure (EE).

OBJECTIVE

We compared EE as estimated by indirect methods (physical activity records and recall questionnaires) used in epidemiologic studies with EE obtained from doubly labeled water (EE(DLW)) in free-living men.

DESIGN

We determined EE(DLW), energy intake at weight maintenance, and EE from 7-d physical activity records (EE(Record)) and a 7-d physical activity recall questionnaire (EE(Recall)) in 24 men aged 41 plus minus 2.0 y ( plus minus SEM) with a body mass index (in kg/m(2)) of 25.1 plus minus 0.5.

RESULTS

There was excellent agreement between EE(DLW) (13.27 plus minus 0.35 MJ/d) and energy intake (13.19 plus minus 0.36 MJ/d), with a difference of 0.5 plus minus 1.0% ( plus minus SE). The indirect measures of physical activity and EE were 14.17 plus minus 0.37 MJ/d for EE(Record) (difference from EE(DLW): 7.9 plus minus 3.2%) and 17.40 plus minus 1.45 MJ/d for EE(Recall) (difference from EE(DLW): 30.6 plus minus 9.9%).

CONCLUSIONS

Seven-day physical activity records provide an acceptable estimate of EE in free-living adults compared with EE(DLW), but 7-d physical activity recalls have limited application to estimate daily EE. For optimal validity, the 7-d physical activity records require good subject compliance and the provision of careful instructions for their use.

A comparison of two methods to ascertain dietary intake: the CARDIA Study

Data on dietary intake were collected in the Coronary Artery Risk Development in Young Adults (CARDIA) Study at the baseline examination in 1985-86 and again at the second examination 2 years later. At baseline, a diet history questionnaire developed for the CARDIA study was used; at the second exam the NCI (Block) food frequency questionnaire was used. The purpose of the present report is to compare the estimated nutrient intakes obtained with the two instruments; to compare correlations of nutrient intakes obtained at the two exams with those observed for other lifestyle and physiological variables also measured 2 years apart; and to assess ability to test hypotheses relating 2-year changes in risk factors to between-exam differences in reported nutrient intakes. Mean levels of reported intake were generally greater for both blacks and whites on the CARDIA diet history than on the Block food frequency. Rank order correlations of reported nutrient intakes between the two questionnaires indicated greater consistency between instruments for whites (r's ranging between 0.35 and 0.52) than for blacks (r's ranging between 0.29 and 0.45). Correlations over time for nutrients were smaller than those observed for body size measures and lipid levels but were similar in magnitude to those for blood pressure, physical activity, and life events. At both exams, total caloric intake was positively associated with physical activity (range of r's for CARDIA were 0.07 for white women to 0.23 for black men, the range of r's for Block were 0.06 for women to 0.11 for white men). Using data from the two examinations, 2-year changes in total plasma cholesterol were significantly related to 2 year changes in Keys scores. The results of this comparison are useful in that they show similarities and differences between two instruments developed to gather dietary intake data. The study also illustrates the need to monitor young adults during a time when rapid changes occur in many lifestyle and physiologic factors.

Does body fatness modify the association between dietary cholesterol and risk of coronary death? Results from the Chicago Western Electric Study

The hypothesis that body fatness modifies the relation between dietary cholesterol and 25-year coronary mortality was examined in a cohort of 1,792 middle-aged men employed by the Western Electric Company in Chicago. Relative risks of coronary death (and 95% confidence intervals) associated with a 225 mg/day greater intake of dietary cholesterol for men with a subscapular skinfold thickness less than or equal to 14, 15-20, and greater than or equal to 21 mm were 1.44 (1.10-1.90), 1.07 (0.84-1.36), and 0.95 (0.76-1.20), respectively, after adjustment for age; serum total cholesterol level; systolic blood pressure; cigarette smoking; family history of cardiovascular disease; evidence of major organ system disease at baseline; and intake of saturated fatty acids, polyunsaturated fatty acids, energy, and ethanol. Adjusted relative risks associated with a 15-mm greater subscapular skinfold thickness for men with a dietary cholesterol intake less than or equal to 649, 650-799, and greater than or equal to 800 mg/day were 1.76 (1.04-2.98), 1.64 (1.04-2.57), and 1.00 (0.69-1.55), respectively. Fatter men apparently did not benefit from a diet lower in cholesterol, while men who ate a diet high in cholesterol apparently did not benefit from leanness. These results support the hypothesis that body fatness modifies the relation between dietary cholesterol and coronary mortality, perhaps because leaner men are more responsive than fatter men to the effects of dietary cholesterol on the concentration of low density lipoprotein cholesterol.

Relationships between blood pressure and measures of dietary energy intake, physical fitness, and physical activity in Australian children aged 11-12 years

STUDY OBJECTIVE

The aim was to examine associations between blood pressure and dietary energy intake, physical activity, and physical fitness in Australian children.

DESIGN

The study was a survey of year 7 children attending schools in metropolitan Perth.

SETTING

Survey schools were located in suburbs representative of the range of socioeconomic strata in metropolitan Perth.

PARTICIPANTS

Data were obtained on 1311 out of 2045 eligible children (64%). The sample included 681 boys and 630 girls. Mean age was 12.0 (SD 0.4) years.

MEASUREMENTS AND MAIN RESULTS

Triplicate blood pressure measurements were obtained using a Dinamap oscillometric recorder. Dietary energy intakes were computed from two week day 24 h records. Physical activity was assessed using questionnaires. Physical fitness was measured using a shuttle run test. Additional measurements included weight, height, and skinfold thickness at four sites. A previous observation of an inverse relationship between diastolic blood pressure and dietary energy intake in boys was confirmed. There was evidence of an inverse relationship in girls but not in boys between blood pressure and physical activity. There was little evidence of relationships between blood pressure and physical fitness.

CONCLUSIONS

Compared with weight and body mass index, dietary energy intake and the chosen measures of physical activity and physical fitness are poor predictors of blood pressure in the population studied.