Rationale, design and baseline characteristics of a randomized controlled trial of a web-based computer-tailored physical activity intervention for adults from Quebec City.

BACKGROUND: The relationship between physical activity and cardiovascular disease (CVD) protection is well documented. Numerous factors (e.g. patient motivation, lack of facilities, physician time constraints) can contribute to poor PA adherence. Web-based computer-tailored interventions offer an innovative way to provide tailored feedback and to empower adults to engage in regular moderate- to vigorous-intensity PA. To describe the rationale, design and content of a web-based computer-tailored PA intervention for Canadian adults enrolled in a randomized controlled trial (RCT). METHODS/DESIGN: 244 men and women aged between 35 and 70 years, without CVD or physical disability, not participating in regular moderate- to vigorous-intensity PA, and familiar with and having access to a computer at home, were recruited from the Quebec City Prospective Urban and Rural Epidemiological (PURE) study centre. Participants were randomized into two study arms: 1) an experimental group receiving the intervention and 2) a waiting list control group. The fully automated web-based computer-tailored PA intervention consists of seven 10- to 15-min sessions over an 8-week period. The theoretical underpinning of the intervention is based on the I-Change Model. The aim of the intervention was to reach a total of 150 min per week of moderate- to vigorous-intensity aerobic PA. DISCUSSION: This study will provide useful information before engaging in a large RCT to assess the long-term participation and maintenance of PA, the potential impact of regular PA on CVD risk factors and the cost-effectiveness of a web-based computer-tailored intervention. TRIAL REGISTRATION: ISRCTN36353353 registered on 24/07/2014.

"Healthy," "diet," or "hedonic". How nutrition claims affect food-related perceptions and intake?

The main purpose of this study was to investigate the impact of nutrition claims on food perceptions and intake among adult men and women, during ad libitum snacks. In a three (healthy vs. diet vs. hedonic) by two (normal-weight vs. overweight/obese) by two (unrestrained vs. restrained eaters) factorial design, 164 men and 188 women were invited to taste and rate oatmeal-raisin cookies. Despite the fact that the cookies were the same in all conditions, they were perceived as being healthier in the "healthy" condition than in the "diet" and "hedonic" conditions. The caloric content was estimated as higher by participants in the "hedonic" than in the "healthy" condition, by women than by men, and by restrained than by unrestrained eaters. Although measured ad libitum cookie intake did not differ as a function of experimental condition, overweight restrained men ate more than did women from each BMI and restraint category. Conversely, overweight restrained women ate less than did men from each BMI and restraint category. In conclusion, our manipulations of healthiness and "fatteningness" of food were effective in changing perceptions, but were not in changing behavior.

Effectiveness of a web-based computer-tailored intervention promoting physical activity for adults from Quebec City: a randomized controlled trial.

BACKGROUND: The primary objective of this study was to determine the effectiveness of a 3-month web-based computer-tailored intervention on moderate-to-vigorous physical activity (MVPA) in adults. METHODS: A total of 242 Canadian adults aged between 35 and 70 years were randomized to an experimental group receiving the intervention or a waiting list control group. The fully automated web-based computer-tailored physical activity intervention consists of seven 10- to 15-min sessions over an 8-week period. The theoretical underpinning of the intervention is based on the I-Change Model. RESULTS: A repeated-measures ANOVA using a linear mixed model showed a significant 'group-by-time' interaction favoring the intervention group in self-reported MVPA (p = .02). The MVPA was similar in both groups at baseline (mean ± SD; 176 ± 13 vs. 172 ± 15 min/week, p = .72) and higher in the intervention than in the control group at a 3-month follow-up (259 ± 21 vs. 201 ± 22 min/week, p = .04). This finding was comparable across women and men (group-by-sex, p = .57) and across participants meeting or not physical activity guidelines at baseline (group-by-baseline physical activity, p = .43). Although engagement to the web-based sessions declined over time, participants completing more web sessions achieved higher self-reported MVPA (p < .05). CONCLUSION: These findings suggest that this intervention is effective in enhancing self-reported MVPA in this adult population in the short term; however, this needs to be confirmed in a larger trial with better engagement to the web-based sessions.

Assessment of Dietary Sodium and Potassium in Canadians Using 24-Hour Urinary Collection.

BACKGROUND: Although salt intake derived from data on urinary sodium excretion in free-living populations has been used in public policy, a population study on urinary sodium excretion has not been done in Canada. We assessed dietary sodium and potassium intake using a 24-hour urine collection in a large survey of urban and rural communities from 4 Canadian cities and determined the association of these electrolytes with blood pressure (BP). METHODS: One thousand seven hundred consecutive individuals, aged 37-72 years, attending their annual follow-up visits of the ongoing Prospective and Urban Rural Epidemiology (PURE) study in Vancouver, Hamilton, Ottawa, and Quebec City, Canada, collected a 24-hour urine sample using standardized procedures. RESULTS: Mean sodium excretion was 3325 mg/d and mean potassium excretion was 2935 mg/d. Sodium excretion ranged from 3093 mg/d in Vancouver to 3642 mg/d in Quebec City, after adjusting for covariates. Potassium excretion ranged from 2844 mg/d in Ottawa to 3082 mg/d in Quebec City. Both electrolytes were higher in men than in women and in rural populations than in urban settings (P < 0.001 for all). Sodium excretion was between 3000 and 6000 mg/d in 48.3% of the participants, < 3000 mg/d in 46.7%, and > 6000 mg/d in only 5%. No significant association between sodium or potassium excretion and BP was found. CONCLUSIONS: Sodium consumption in these Canadians is within a range comparable to other Western countries, and intake in most individuals is < 6000 mg/d, with only 5% at higher levels. Within this range, sodium or potassium levels were not associated with BP.