Fruit and vegetable intake and eating behaviors mediate the effect of a randomized text-message based weight loss program.

INTRODUCTION: We hypothesized that fruit/vegetable intake and eating behaviors mediate the relationship between experimental condition and weight loss in a randomized trial evaluating a text-message based weight loss program. METHODS: Overweight/obese individuals from San Diego, CA (N = 52 with complete data) were randomly assigned in 2007 into one of two groups for four months: 1) the intervention group that received 2-5 weight management text-messages p/day; 2) the usual-care comparison group. Three 24-hour recalls assessed fruit/vegetable intake change and the eating behavior inventory (EBI) measured change in eating behaviors. Regression path models tested intervention mediation. RESULTS: Direct effects of the intervention were found for change in body weight (b = -3.84, R(2) = 0.074), fruit/vegetable intake (b = 2.00, R(2) = 0.083), and EBI scores (b = 7.15, R(2) = 0.229) (ps < 0.05). The treatment group to weight change path was not statistically significant (b = -0.673, R(2) = 0.208) when fruit/vegetable intake change and EBI score change were specified as intervention mediators in the model. The total indirect effect was 3.17 lb indicating that the indirect paths explained 82.6% of the total effect on weight change. DISCUSSION: Fruit/vegetable intake and eating behaviors mediated the intervention's effect on weight change. The findings suggest that sending text-messages that promote healthy eating strategies resulted in moderate short-term weight loss.

Is television viewing a suitable marker of sedentary behavior in young people?

BACKGROUND: Television (TV) viewing is a highly prevalent sedentary behavior in young people and has played a significant role in the assessment of sedentary behaviors. An important question to be addressed is to what extent TV viewing is a suitable indicator, or marker, of overall levels of sedentary behavior in children and adolescents. This has not yet been attempted in youth, but has already been attempted in Australian adults. PURPOSE: This study was conducted to test whether TV viewing in UK teenagers is a marker of sedentary behavior more broadly and to see if the results mirror those of Australian adults. METHODS: Ecological momentary assessment time-use diaries were completed by 561 boys and 923 girls (mean age 14.67 years) in which weekday and weekend out-of-school time behaviors were recorded every 15 min. RESULTS: TV viewing was negatively associated with other leisure-time sedentary behaviors for both boys and girls for weekdays and weekends. Higher levels of TV viewing were associated with less time in other key sedentary behaviors, such as computer use in boys and motorized transport in girls. CONCLUSIONS: TV viewing appears not to reflect additional time in other sedentary behaviors in British teenagers, in contrast to data from Australian women. Studies of sedentary behavior should encompass as wide a range of behaviors as possible.

Family circumstance, sedentary behaviour and physical activity in adolescents living in England: Project STIL.

BACKGROUND: Identification of non-modifiable correlates of physical activity and sedentary behaviour in youth contributes to the development of effective targeted intervention strategies. The purpose of this research was to examine the relationships between family circumstances (e.g. socio-economic status, single vs. dual parent household, presence/absence of siblings) and leisure-time physical activity and sedentary behaviours in adolescents. METHODS: A total of 1171 adolescents (40% male; mean age 14.8 years) completed ecological momentary assessment diaries every 15 minutes for 3 weekdays outside of school hours and 1 weekend day. Analysed behaviours were sports/exercise, active travel, TV viewing, computer use, sedentary socialising (hanging-out, using the telephone, sitting and talking) and total sedentary behaviour. Linear regression was employed to estimate levels of association between individual family circumstance variables and each behaviour. RESULTS: Compared to girls from higher socioeconomic status (SES) groups, girls from low SES groups reported higher weekend TV viewing and higher weekday total sedentary behaviour. For boys, single parent status was associated with greater total sedentary behaviour compared to those from dual parent households. Boys and girls from low socio-economic neighbourhoods reported lower participation in sports/exercise compared to those living in higher socio-economic neighbourhoods. CONCLUSION: Associations were not consistent across behaviours or between genders. Overall, findings indicate that boys from single parent households and girls from low socio-economic families may be at increased risk of high sedentary behaviour. Those living in low socioeconomic neighbourhoods may be at increased risk of reduced participation in sports and exercise.

The prevalence of sedentary behavior and physical activity in leisure time: A study of Scottish adolescents using ecological momentary assessment.

OBJECTIVE: To report time and prevalence of leisure time sedentary and active behaviors in adolescents. METHOD: Cross-sectional, stratified, random sample from schools in 14 districts in Scotland, 2002-03, using ecological momentary assessment (n=385 boys, 606 girls; mean age 14.1 years; range 12.6-16.7 years). This is a method of capturing current behavioral episodes. We used 15 min time intervals. RESULTS: Television viewing occupied the most leisure time. The five most time consuming sedentary activities occupied 228 min per weekday and 396 min per weekend day for boys, and 244 min per weekday and 400 min per weekend day for girls, with TV occupying one-third to one-half of this time. In contrast, 62 min was occupied by active transport and sports/exercise per weekday and 91 min per weekend day for boys, with 55 min per weekday and 47 min per weekend day for girls. A minority watched more than 4 h of TV per day, with more at weekends. Other main sedentary behaviors for boys were homework, playing computer/video games, and motorised transport and, for girls, homework, motorised transport, and sitting and talking. CONCLUSION: Scottish adolescents engage in a variety of sedentary and active behaviors. Research into sedentary behavior must assess multiple behaviors and not rely solely on TV viewing.

Temporal and environmental patterns of sedentary and active behaviors during adolescents' leisure time.

BACKGROUND: There is great interest in young people's overweight and obesity. Few data, however, describe when sedentary and physically active behaviors are likely to occur during the day or how these behaviors are related to location. PURPOSE: The purpose of this study was to describe sedentary and active leisure-time behaviors of adolescents across the day and setting. METHOD: Adolescents (male n = 579, female n = 967; aged 13-16 years) completed time-use diaries for three weekdays and one weekend day. At 15 min intervals, participants recorded what they were doing and where they were. RESULTS: TV viewing and sports/exercise peaked at different times in the day, although TV viewing was two to three times more likely to occur than sports/exercise. TV viewing was most likely to occur during the middle to late evening. The playing of computer games was low, particularly for girls. Weekend data showed TV viewing was the most reported activity throughout the day. For boys, "being in the garden" was highly predictive of engaging in sports/exercise, but this declined rapidly with age. Motorized travel to school was reported twice as often as active travel. CONCLUSION: Momentary assessments of behavior, in conjunction with contemporaneous reports of environmental factors, describe important patterns of leisure-time active and sedentary behaviors in youth.

Race/ethnicity, social class, and leisure-time physical inactivity.

PURPOSE: The aims of this study were to determine 1) prevalence of leisure-time physical inactivity in a nationally representative sample of non-Hispanic white, non-Hispanic black, and Hispanic men and women; 2) prevalence of leisure-time inactivity by racial/ethnic group across social class indicators; and 3) the relationship between leisure-time inactivity and occupational physical activity, independent of other social class indicators. METHODS: The National Physical Activity and Weight Loss Survey was a telephone survey of noninstitutionalized U.S. adults (4695 men, 6516 women) conducted by random digit dialing between September and December 2002. Self-reported physical activity was assessed using questions from the 2001 Behavioral Risk Factor Surveillance System. Respondents who reported no moderate- or vigorous-intensity physical activity during leisure time in a usual week were classified as inactive. Indicators of social class were education, family income, employment status, and marital status. RESULTS: Age-adjusted prevalence of leisure-time inactivity was 9.9% +/- 0.6 SE (standard error) and 12.0 +/- 0.6 for white men and women, respectively; 19.0 +/- 2.5 and 25.2 +/- 2.1 for non-Hispanic black men and women, and 20.9 +/- 2.1 and 27.3 +/- 2.5 for Hispanic men and women. Within each racial/ethnic group, prevalence of leisure-time inactivity was highest among participants of lower social class. Differences in inactivity by racial/ethnic group were less evident after adjustment for social class. Odds of inactivity were similar across quartiles of occupational physical activity after adjustment for age, sex, and social class. CONCLUSIONS: Non-Hispanic blacks and Hispanics were more inactive during their leisure time than were non-Hispanic whites. Social class but not occupational physical activity seems to moderate the relationship between race/ethnicity and leisure-time physical inactivity.

Tackling the obesity pandemic: a call for sedentary behaviour research.

An emerging threat to public health is seen in the dramatic rise in obesity status of Canadians, especially among young people. In addressing the possible factors responsible for these dramatic increases, this paper outlines the importance of understanding sedentariness as an important health behaviour, distinct from physical activity, and identifying the modifiable determinants of sedentary behaviours.

The Role of Stress in Understanding Differences in Sedentary Behavior in Hispanic/Latino Adults: Results From the Hispanic Community Health Study/Study of Latinos Sociocultural Ancillary Study.

BACKGROUND: Chronic stress and/or lifetime traumatic stress can create a self-reinforcing cycle of unhealthy behaviors, such as overeating and sedentary behavior, that can lead to further increases in stress. This study examined the relationship between stress and sedentary behavior in a sample of Hispanic/Latino adults (N = 4244) from the Hispanic Community Health Study/Study of Latinos Sociocultural Ancillary Study. METHODS: Stress was measured as the number of ongoing difficulties lasting 6 months or more and as lifetime exposure to traumatic events. Sedentary behavior was measured by self-report and with accelerometer. Multivariable regression models examined associations of stress measures with time spent in sedentary behaviors adjusting by potential confounders. RESULTS: Those who reported more than one chronic stressor spent, on average, 8 to 10 additional minutes per day in objectively measured sedentary activities (P < .05), whereas those with more than one lifetime traumatic stressor spent (after we adjusted for confounders) 10 to 14 additional minutes in sedentary activities (P < .01) compared with those who did not report any stressors. Statistical interactions between the 2 stress measures and age or sex were not significant. CONCLUSION: Interventions aimed at reducing sedentary behaviors might consider incorporating stress reduction into their approaches.

Using social and mobile tools for weight loss in overweight and obese young adults (Project SMART): a 2 year, parallel-group, randomised, controlled trial.

BACKGROUND: Few weight loss interventions are evaluated for longer than a year, and even fewer employ social and mobile technologies commonly used among young adults. We assessed the efficacy of a 2 year, theory-based, weight loss intervention that was remotely and adaptively delivered via integrated user experiences with Facebook, mobile apps, text messaging, emails, a website, and technology-mediated communication with a health coach (the SMART intervention). METHODS: In this parallel-group, randomised, controlled trial, we enrolled overweight or obese college students (aged 18-35 years) from three universities in San Diego, CA, USA. Participants were randomly assigned (1:1) to receive either the intervention (SMART intervention group) or general information about health and wellness (control group). We used computer-based permuted-block randomisation with block sizes of four, stratified by sex, ethnicity, and college. Participants, study staff, and investigators were masked until the intervention was assigned. The primary outcome was objectively measured weight in kg at 24 months. Differences between groups were evaluated using linear mixed-effects regression within an intention-to-treat framework. Objectively measured weight at 6, 12, and 18 months was included as a secondary outcome. The trial is registered with ClinicalTrials.gov, number NCT01200459. FINDINGS: Between May 18, 2011, and May 17, 2012, 404 individuals were randomly assigned to the intervention (n=202) or control (n=202). Participants' mean (SD) age was 22·7 (3·8) years. 284 (70%) participants were female and 125 (31%) were Hispanic. Mean (SD) body-mass index at baseline was 29·0 (2·8) kg/m(2). At 24 months, weight was assessed in 341 (84%) participants, but all 404 were included in analyses. Weight, adjusted for sex, ethnicity, and college, was not significantly different between the groups at 24 months (-0·79 kg [95% CI -2·02 to 0·43], p=0·204). However, weight was significantly less in the intervention group compared with the control group at 6 months (-1·33 kg [95% CI -2·36 to -0·30], p=0·011) and 12 months (-1·33 kg [-2·30 to -0·35], p=0·008), but not 18 months (-0·67 kg [95% CI -1·69 to 0·35], p=0·200). One serious adverse event in the intervention group (gallstones) could be attributable to rapid and excessive weight loss. INTERPRETATION: Social and mobile technologies did not facilitate sustained reductions in weight among young adults, although these approaches might facilitate limited short-term weight loss. FUNDING: The National Heart, Lung, and Blood Institute of the National Institutes of Health (U01 HL096715).

Accelerometer adherence and performance in a cohort study of US Hispanic adults.

PURPOSE: This study described participant adherence to wearing the accelerometer and accelerometer performance in a cohort study of adults. METHODS: From 2008 to 2011, 16,415 US Hispanic/Latino adults age 18-74 yr enrolled in the Hispanic Community Health Study/Study of Latinos. Immediately after the baseline visit, participants wore an Actical accelerometer for 1 wk. This study explored correlates of accelerometer participation and adherence, defined as wearing it for at least three of a possible six days for ≥10 h·d. Accelerometer performance was assessed by exploring the number of different values of accelerometer counts per minute for each participant. RESULTS: Overall, 92.3% (n = 15,153) had at least 1 d with accelerometer data and 77.7% (n = 12,750) were adherent. Both accelerometer participation and adherence were higher among participants who were married or partnered, reported a higher household income, were first-generation immigrants, or reported lower sitting time. Participation was also higher among those with no stair limitations. Adherence was higher among participants who were male, older, employed or retired, not US born, preferred Spanish over English, reported higher work activity or lower recreational activity, and with a lower body mass index. Among the sample that met the adherence definition, the maximum recorded count per minute was 12,000, and there were a total of 5846 different counts per minute. On average, participants had 112.5 different counts per minute over 6 d (median, 106; interquartile range, 91-122). The number of different counts per minute was higher among men, younger ages, normal weight, and those with higher accelerometer-assessed physical activity. CONCLUSION: Several correlates differed between accelerometer participation and adherence. These characteristics could be targeted in future studies to improve accelerometer wear. The performance of the accelerometer provided insight into creating a more accurate nonwear algorithm.

Clinical trial management of participant recruitment, enrollment, engagement, and retention in the SMART study using a Marketing and Information Technology (MARKIT) model.

Advances in information technology and near ubiquity of the Internet have spawned novel modes of communication and unprecedented insights into human behavior via the digital footprint. Health behavior randomized controlled trials (RCTs), especially technology-based, can leverage these advances to improve the overall clinical trials management process and benefit from improvements at every stage, from recruitment and enrollment to engagement and retention. In this paper, we report the results for recruitment and retention of participants in the SMART study and introduce a new model for clinical trials management that is a result of interdisciplinary team science. The MARKIT model brings together best practices from information technology, marketing, and clinical research into a single framework to maximize efforts for recruitment, enrollment, engagement, and retention of participants into a RCT. These practices may have contributed to the study's on-time recruitment that was within budget, 86% retention at 24 months, and a minimum of 57% engagement with the intervention over the 2-year RCT. Use of technology in combination with marketing practices may enable investigators to reach a larger and more diverse community of participants to take part in technology-based clinical trials, help maximize limited resources, and lead to more cost-effective and efficient clinical trial management of study participants as modes of communication evolve among the target population of participants.

Accelerometer-measured sedentary time among Hispanic adults: Results from the Hispanic Community Health Study/Study of Latinos (HCHS/SOL).

Excessive sedentary behavior is associated with negative health outcomes independent of physical activity. Objective estimates of time spent in sedentary behaviors are lacking among adults from diverse Hispanic/Latino backgrounds. The objective of this study was to describe accelerometer-assessed sedentary time in a large, representative sample of Hispanic/Latino adults living in the United States, and compare sedentary estimates by Hispanic/Latino background, sociodemographic characteristics and weight categories. This study utilized baseline data from the Hispanic Community Health Study/Study of Latinos (HCHS/SOL) that included adults aged 18-74 years from four metropolitan areas (N = 16,415). Measured with the Actical accelerometer over 6 days, 76.9% (n = 12,631) of participants had > 10 h/day and > 3 days of data. Participants spent 11.9 h/day (SD 3.0), or 74% of their monitored time in sedentary behaviors. Adjusting for differences in wear time, adults of Mexican background were the least (11.6 h/day), whereas adults of Dominican background were the most (12.3 h/day), sedentary. Women were more sedentary than men, and older adults were more sedentary than younger adults. Household income was positively associated, whereas employment was negatively associated, with sedentary time. There were no differences in sedentary time by weight categories, marital status, or proxies of acculturation. To reduce sedentariness among these populations, future research should examine how the accumulation of various sedentary behaviors differs by background and region, and which sedentary behaviors are amenable to intervention.

Environmental interventions for eating and physical activity: a randomized controlled trial in middle schools.

BACKGROUND: Our objective was to evaluate the effects of environmental, policy, and social marketing interventions on physical activity and fat intake of middle school students on campus. DESIGN: Twenty-four middle schools were randomly assigned to intervention or control conditions. Baseline measures were collected in spring 1997, and interventions were conducted during the 1997-1998 and 1998-1999 school years SETTING/PARTICIPATION: The schools had mean enrollments of 1109, with 44.5% nonwhite students. Over 2 years, physical activity interventions were designed to increase physical activity in physical education classes and throughout the school day. Nutrition interventions were designed to provide and market low-fat foods at all school food sources, including cafeteria breakfasts and lunches, a la carte sources, school stores, and bag lunches. School staff and students were engaged in policy change efforts, but there was no classroom health education. MAIN OUTCOMES MEASURES: Primary outcomes were measured by direct observation and existing records. RESULTS: Randomized regression models (N =24 schools) revealed a significant intervention effect for physical activity for the total group (p <0.009) and boys (p <0.001), but not girls (p <0.40). The intervention was not effective for total fat (p <0.91) or saturated fat (p <0.79). Survey data indicated that the interventions reduced reported body mass index for boys (p <0.05). CONCLUSIONS: Environmental and policy interventions were effective in increasing physical activity at school among boys but not girls. The interventions were not effective in reducing fat intake at school. School environmental and policy interventions have the potential to improve health behavior of the student population, but barriers to full implementation need to be better understood and overcome.

Evaluation of a two-year middle-school physical education intervention: M-SPAN.

PURPOSE: School physical education (PE) is highly recommended as a means of promoting physical activity, and randomized studies of health-related PE interventions in middle schools have not been reported. We developed, implemented, and assessed an intervention to increase physical activity during middle-school PE classes. METHODS: Twenty-four middle schools (approximately 25,000 students, 45% nonwhite) in Southern California participated in a randomized trial. Schools were assigned to intervention (N = 12) or control (N = 12) conditions, and school was the unit of analysis. A major component of the intervention was a 2-yr PE program, which consisted of curricular materials, staff development, and on-site follow-up. Control schools continued usual programs. Student activity and lesson context were observed in 1849 PE lessons using a validated instrument during baseline and intervention years 1 and 2. RESULTS: The intervention significantly (P = 0.02) improved student moderate to vigorous physical activity (MVPA) in PE, by approximately 3 min per lesson. Effects were cumulative; by year 2 intervention schools increased MVPA by 18%. Effect sizes were greater for boys (d = 0.98; large) than girls (d = 0.68; medium). CONCLUSIONS: A standardized program increased MVPA in middle schools without requiring an increase in frequency or duration of PE lessons. Program components were well received by teachers and have the potential for generalization to other schools. Additional strategies may be needed for girls.

Physical activity and sedentary behaviours in youth: issues and controversies.

There is growing concern over the effects of sedentary lifestyles on the health of young people. Recent rapid increases in juvenile obesity have received a great deal of attention in the scientific and popular press and have been attributed partly to television viewing, computer games and other sedentary behaviours. These are thought to compete with physical activity. There is a 'moral panic' concerning the 'couch kids' culture in modern western society. Project STIL (Sedentary Teenagers and Inactive Lifestyles) at Loughborough University is investigating 'what young people do' and focuses on active and inactive pursuits chosen in their leisure time. The following issues are addressed in this paper with specific reference to young people: how do we define 'sedentary behaviour' and do key sedentary behaviours displace physical activity? Are key sedentary behaviours obesogenic? What are the secular trends for children and youth for TV viewing? Our results for young people suggest that: 1. TV viewing and video-game playing are largely uncorrelated with physical activity, suggesting that there is time for both 2. meta-analytic findings show that body fatness is not related in any clinically meaningful way with key sedentary behaviours 3. although more children and youth have greater access to TVs than in previous generations, the amount of TV watched per head has not changed for 40 years. Preliminary findings from Project STIL suggest that inactivity is more complex that we sometimes think. Indeed, measures of 'couch potato-ism', such as TV viewing, may be inappropriate markers of inactivity.

A prospective study of sedentary behavior and changes in the body mass index distribution.

PURPOSE: We aimed to determine whether baseline sedentary behavior was associated with changes in body mass index (BMI) over 9 yr. METHODS: Participants were enrolled into the National Institutes of Health American Association of Retired Persons (NIH-AARP) Diet and Health study in 1995-1996 (median age, 63 yr), and BMI was reported at baseline and 9 yr later (n = 158,436). Sitting time (<3 (referent), 3-4, 5-6, 7-8, or ≥9 h·d), television viewing (none, <1, 1-2, 3-4, 5-6, 7-8, or ≥9 h·d), and the covariates (age, sex, race, education, smoking, moderate-to-vigorous physical activity, caloric intake, and sleep duration) were reported at baseline. We used longitudinal quantile regression to model changes at the 10th, 25th, 50th, 75th, and 90th BMI percentiles. RESULTS: More sitting at baseline was associated with additional increases in BMI over time, and the association was stronger at the upper BMI percentiles (e.g., <3 (referent) vs 5-6 h·d of sitting additional increases: 50th percentile = 0.41 kg·m and 95% confidence interval (CI) = 0.34-0.48; 90th percentile = 0.85 kg·m and 95% CI = 0.72-0.98). Similar associations were observed between more television viewing at baseline and additional increases in BMI over time (e.g., no television (referent) vs 3-4 h·d of television: 50th percentile = 1.96 kg·m and 95% CI = 1.77-2.15; 90th percentile = 2.11 kg·m and 95% CI = 1.49-2.73). CONCLUSIONS: Reducing sedentary behavior could help prevent an increase in BMI in adulthood especially at the upper percentiles of the BMI distribution and thereby reduce the prevalence of obesity.

Effects of Behavioral Contingencies on Adolescent Active Videogame Play and Overall Activity: A Randomized Trial.

OBJECTIVE: This study evaluated the effect of four active videogames (AVGs) varying in behavioral contingencies (behavior-consequence relations) on adolescent AVG play and overall activity levels over 4 weeks. MATERIALS AND METHODS: Each AVG, manufactured by SSD/Xavix(®) (Shiseido Co. of Japan, Tokyo, Japan), was coded and scored for the number of positive and aversive behavioral contingencies within the games. "Bowling" and "Tennis" were classified as having "higher contingency scores," and "Boxing" and aerobic fitness training were classified as having "lower contingency scores." Adolescents (n=63; 11-15 years old; 62% male; 38% Hispanic; 44% overweight or obese) were randomized to play one of the four AVGs at home and recorded game play sessions in a paper log. Baseline and week 4 assessments were completed at home; week 1, 2, and 3 assessments were completed by telephone. Accelerometers were worn during baseline and weeks 1 and 4. RESULTS: Accelerometer-measured sedentary and light activity hours/day were stable over time, whereas moderate-vigorous physical activity minutes/day increased in the higher contingency group and decreased in the lower contingency group (interaction effect, 6.43, P=0.024). Reported game play minutes decreased in both groups from week 1 to week 4 (-29.42 minutes, P=0.001). DISCUSSION: There was some support for the hypothesis that AVGs with more behavioral contingencies, compared with AVGs with fewer behavioral contingencies, result in more physical activity. However, overall AVG play decreased substantially after the first week. Further study is needed to better understand how behavioral contingencies can be used in AVGs to enhance their potential to provide health benefits to game players.

Objectively measured physical activity is related to cognitive function in older adults.

OBJECTIVES: To explore the relationship between cognitive functioning and time spent at different intensities of physical activity (PA) in free-living older adults. DESIGN: Cross sectional analyses. SETTING: Continuing care retirement communities. PARTICIPANTS: Older adults residing in seven continuing care retirement communities in San Diego County with an average age of 83; 70% were female, and 35% had a graduate-level education (N = 217). MEASUREMENTS: PA was measured objectively using hip worn accelerometers with data aggregated to the minute level. Three cut points were used to assess low light-intensity PA (LLPA), high light-intensity PA (HLPA), and moderate- to vigorous-intensity PA (MVPA). The Trail Making Test (TMT) Parts A and B were completed, and time for each test (seconds) and time for Part B minus time for Part A (seconds) were used as measures of cognitive function. Variables were log-transformed and entered into linear regression models adjusting for demographic factors (age, education, sex) and other PA intensity variables. RESULTS: LLPA was not related to any TMT test score. HLPA was significantly related to TMT A, B, and B minus A but only in unadjusted models. MVPA was related to TMT B and B minus A after adjusting for demographic variables. CONCLUSION: There may be a dose response between PA intensity and cognitive functioning in older adults. The stronger findings supporting a relationship between MVPA and cognitive functioning are consistent with previous observational and intervention studies.

Using step cadence goals to increase moderate-to-vigorous-intensity physical activity.

BACKGROUND: Increasing moderate-to-vigorous-intensity physical activity (MVPA) is an important public health goal. Pedometers are evidence-based devices for increasing daily activity, but studies have not evaluated the comparative efficacy of step cadence goals for increasing MVPA. PURPOSE: This study aimed to evaluate the efficacy of three pedometer-based step goals for increasing MVPA. METHODS: Latina women (n = 180; 18-55 yr, mean body mass index = 31.1, SD = 6.5) were recruited to 12 community centers, which were randomly assigned to one of three conditions. Each group received an identical 12-wk theory-based physical activity (PA) intervention that differed only on the type of daily step goal: 1) a self-selected goal (SELF); 2) a goal of 10,000 steps per day (FREQUENCY); or 3) a goal of 3000 steps in 30 min (CADENCE). Accelerometer-based PA was measured at baseline and after 12 wk. RESULTS: Adjusted multilevel pattern-mixture models using generalized estimating equations revealed that participants in the CADENCE condition engaged in similar levels of postintervention MVPA to those in the SELF and FREQUENCY goal conditions. However, MVPA of participants in the CADENCE condition was more likely to occur in bouts lasting greater than 10 consecutive minutes compared with the MVPA of participants in the SELF (P = 0.01) or FREQUENCY (P = 0001) conditions. CONCLUSIONS: PA interventions should consider including a step cadence goal to help individuals accumulate bout-based MVPA and meet national PA guidelines.

Metabolism and breast cancer risk: frontiers in research and practice.

Fifty years ago the causes of cancer were largely unknown. Since then, it has become clear that a strong relationship exists between obesity and many cancers, particularly postmenopausal breast cancer. A major challenge in understanding the link between obesity and cancer risk has been elucidating the biological basis underlying the association. Although this remains unresolved, the main candidate systems linking adiposity and cancer risk are insulin and the insulin-like growth factor-1 axis, endogenous reproductive hormones, and chronic inflammation. Our purpose is to provide a mechanistic overview of the hypothesized relationship between diet, physical activity, and obesity with breast cancer risk and progression. In addition, we will provide examples of recently funded randomized clinical trials examining metabolic risk factors in relation to breast cancer risk and survival. Additional research is warranted to validate the strength and consistency of the relationships among diet, these biomarkers, and breast cancer risk. As these relationships become clearer, future studies will be needed to develop effective intervention programs to prevent breast cancer and improve cancer prognosis by promoting a healthy lifestyle.