No abstract

A variety of studies has a need to estimate the amount and pattern of daily energy expenditure. To this end, a 3-day activity record was developed and is described. Every 15-min period over 3 days, including a weekend day, was qualified in terms of energy cost on a 1 to 9 scale corresponding to a range of 1.0 MET to 7.8 METs and higher. A reliability study of 61 subjects indicated a highly reproducible procedure as shown by an intraclass correlation of 0.96 for mean kcal of energy expenditure over 3 days. Repeatability was unchanged whether or not the hours of sleep were included in the record. Samples of 150 children and 150 adults were also drawn to investigate the relationship between energy expenditure, physical working capacity, and body fatness. Results support the hypothesis that mean energy expenditure per kg of body weight is significantly correlated with physical working capacity expressed per kg of body weight (r = 0.31; p less than 0.01). Mean energy expenditure per kg of body weight is negatively related to body fat (-0.08 less than or equal to r less than or equal to -0.13). It is concluded that the 3-day activity record is a procedure suitable to estimate energy expenditure in population studies.

CHAPUT, JEAN-PHILIPPE, JEAN-PIERRE DESPRÉ S, CLAUDE BOUCHARD, AND ANGELO TREMBLAY. Short sleep duration is associated with reduced leptin levels and increased adiposity: results from the Québec Family Study. Obesity. 2007;15:253-261. Objective: To explore cross-sectional associations between short sleep duration and variations in body fat indices and leptin levels during adulthood in a sample of men and women involved in the Québec Family Study. Research Methods and Procedures: Anthropometric measurements, plasma lipid-lipoprotein profile, plasma leptin concentrations, and total sleep duration were determined in a sample of 323 men and 417 women ages 21 to 64 years. Results: When compared with adults reporting 7 to 8 hours of sleep per day, the adjusted odds ratio for overweight/ obesity was 1.38 (95% confidence interval, 0.89 to 2.10) for those with 9 to 10 hours of sleep and 1.69 (95% confidence interval, 1.15 to 2.39) for those with 5 to 6 hours of sleep, after adjustment for age, sex, and physical activity level. In each sex, we observed lower adiposity indices in the 7-to 8-hour sleeping group than in the 5-to 6-hour sleeping group. However, all of these significant differences disappeared after statistical adjustment for plasma leptin levels. Finally, the well-documented regression of plasma leptin levels over body fat mass was used to predict leptin levels of short-duration sleepers (5 and 6 hours of sleep), which were then compared with their measured values. As expected, the measured leptin values were significantly lower than predicted values. Discussion: There may be optimal sleeping hours at which body weight regulation is facilitated. Indeed, short sleep duration predicts an increased risk of being overweight/ obese in adults and is related to a reduced circulating leptin level relative to what is predicted by fat mass. Because sleep duration is a potentially modifiable risk factor, these findings might have important clinical implications for the prevention and treatment of obesity.

PROVENCHER, VÉ RONIQUE, VICKY DRAPEAU, ANGELO TREMBLAY, JEAN-PIERRE DESPRÉ S, AND SIMONE LEMIEUX. Eating behaviors and indexes of body composition in men and women from the Québec Family Study. Obes Res. 2003;11:783-792. Objective: To put into relationship the dietary and anthropometric profile of men and women with their eating behaviors (cognitive dietary restraint, disinhibition, and susceptibility to hunger) and to assess whether gender and obesity status influence these associations. Research Methods and Procedures: Anthropometric measurements (including visceral adipose tissue accumulation), dietary profile (3-day food record), and eating behaviors (Three-Factor Eating Questionnaire) were determined in a sample of 244 men and 352 women. Results: Women had significantly higher cognitive dietary restraint and disinhibition scores than men (p Ͻ 0.0001). In both genders, scores for disinhibition and susceptibility to hunger, but not for cognitive dietary restraint, were higher in obese subjects than in overweight and nonobese subjects (p Ͻ 0.05). Positive correlations were observed between rigid restraint and most of the anthropometric variables studied (0.12 Յ r Յ 0.16). Moreover, in women, flexible restraint was negatively associated with body fat and waist circumference (r ϭ Ϫ0.11). Cognitive dietary restraint and rigid restraint were positively related to BMI among nonobese women (0.19 Յ r Յ 0.20), whereas in obese men, cognitive dietary restraint and flexible restraint tended to be negatively correlated with BMI (Ϫ0.20 Յ r Յ Ϫ0.22; p ϭ 0.10). Discussion: Gender could mediate associations observed between eating behaviors and anthropometric profile. It was also found that disinhibition and susceptibility to hunger are positively associated with the level of obesity. On the other hand, cognitive dietary restraint is not consistently related to body weight and adiposity, whereas rigid and flexible restraint are oppositely associated to obesity status, which suggests that it is important to differentiate the subscales of cognitive dietary restraint. Finally, counseling aimed at coping with disinhibition and susceptibility to hunger could be of benefit for the long-term treatment of obesity.

No abstract