Cynthia M. Ferrara

Sex differences in insulin action and body fat distribution in overweight and obese middle-aged and older men and women

Controversy exists as to whether there are differences in insulin action between older men and women, and what factors contribute to these differences. This study tests the hypothesis that sex differences in regional fat distribution contribute to a disparity in insulin sensitivity in older men vs. older women. Healthy, older (50-71 years), sedentary men (n = 28) and women (n = 29) were recruited to participate in the study. Body fat, fat-free mass (FFM), and visceral (VAT) and subcutaneous abdominal (SAT) adipose tissue areas were measured by DXA and computed tomography (CT). For measurements of insulin-stimulated glucose disposal (M), insulin was infused at a constant rate of 240 pmol.m(-2).min(-1), and M was calculated between the 90th and 120th min of the hyperinsulinemic-euglycemic clamp. The men weighed 16% more and had 16% higher waist and 4% lower hip circumferences than women (p < 0.05 for all). Total fat mass and SAT were 21% and 33% lower and FFM was 49% higher in men than in women, whereas waist-to-hip ratio (WHR) and VAT:SAT ratio were 21% and 56% higher in men than in women (p < 0.05 for all). Although insulin concentrations during the glucose clamp were higher in men, M was 47% lower in men vs. women (21.7 +/- 1.1 vs. 46.7 +/- 3.1 micromol.L(-1).kg FFM(-1).min(-1), p < 0.05). The sex-related differences in M persisted after controlling for insulin concentrations during the glucose clamp, for waist, WHR, and VAT:SAT. Older men are more insulin resistant than women, despite lower body fat and subcutaneous abdominal fat. This difference in insulin sensitivity is not explained by abdominal fat distribution, therefore other metabolic factors contribute to the sex differences in insulin sensitivity.

An online social network to increase walking in dog owners: a randomized trial

PURPOSE Encouraging dog walking may increase physical activity in dog owners. This cluster-randomized controlled trial investigated whether a social networking Web site (Meetup™) could be used to deliver a multicomponent dog walking intervention to increase physical activity. METHODS Sedentary dog owners (n = 102) participated. Eight neighborhoods were randomly assigned to the Meetup™ condition (Meetup™) or a condition where participants received monthly e-mails with content from the American Heart Association regarding increasing physical activity. The Meetup™ intervention was delivered over 6 months and consisted of newsletters, dog walks, community events, and an activity monitor. The primary outcome was steps; secondary outcomes included social support for walking, sense of community, perceived dog walking outcomes, barriers to dog walking, and feasibility of the intervention. RESULTS Mixed-model analyses examined change from baseline to postintervention (6 months) and whether change in outcomes differed by condition. Daily steps increased over time (P = 0.04, d = 0.28), with no differences by condition. The time-condition interaction was significant for the perceived outcomes of dog walking (P = 0.04, d = 0.40), such that the Meetup™ condition reported an increase in the perceived positive outcomes of dog walking, whereas the American Heart Association condition did not. Social support, sense of community, and dog walking barriers did not significantly change. Meetup™ logins averaged 58.38 per week (SD, 11.62). Within 2 months of the intervention ending, organization of the Meetup™ groups transitioned from the study staff to Meetup™ members. CONCLUSIONS Results suggest that a Meetup™ group is feasible for increasing physical activity in dog owners. Further research is needed to understand how to increase participation in the Meetup™ group and facilitate greater connection among dog owners.

Barriers and facilitators to dog walking in New England

Dog walking may increase physical activity among dogs and their owners. Understanding barriers and facilitators to walking the dog is critical to developing interventions to increase dog walking. This study aimed to confirm previously identified barriers and facilitators of dog walking, and to identify unique factors that may be relevant to dog walking in cities with variable weather. This mixed methods study used focus groups to identify barriers and facilitators associated with dog walking and a survey to examine which factors were associated with dog walking. Focus group participants described barriers, such as lack of time, weather, lack of places to walk and the dogs bad behaviour. Facilitators included enjoyment, dog walking norms (defined as the participants perception of how much the veterinarian, other dog owners, and their family think they should walk the dog), and socialisation opportunities. A hierarchical regression analysis of survey data revealed that the participants perception of dog ...

Feasibility of a social networking site to promote physical activity in adults

The purpose of this study is to examine the feasibility of a social networking website on promoting physical activity in an ethnically diverse group of adults. Participants were recruited from English classes at an urban adult education center. Initial measurements included height, weight, and a study-specific survey about exercise and social media use. Participants were invited to join a social networking website as part of an 8-week intervention to promote physical activity. Feasibility of the intervention was determined by analysis of the website use and post-intervention focus groups. Eighteen individuals completed baseline testing and were invited to join the social networking group (4 males, 14 females, 35 ± 13 years of age, mean ± standard deviation). Only six study participants (all women) joined the social networking group. Website visits significantly decreased from the first month to the second month, but participants spent significantly more time per visit during the second compared to the first month. Participants found the website easy to use and informative. Barriers to joining the networking group included time and internet access. Although a social networking site may be utilized to promote healthy behaviors, there are barriers that limit participation in this type of intervention, particularly in a group of ethnically diverse adults. Future studies need to examine how to encourage participants to join and how to effectively use a social networking group to promote physical activity.