Physical activity and lipids and lipoproteins in American Indians ages 45-74

Implementation of a multilevel, multicomponent intervention for obesity control in Native American communities (OPREVENT2): challenges and lessons learned

OPREVENT2 was a multilevel, multicomponent (MLMC) adult obesity prevention that sought to improve access and demand for healthier food and physical activity opportunities in six Native American communities in the Southwest and Midwest. OPREVENT2 worked with worksites, food stores, schools (grades 2-6), through social media and mailings, and with a local community action committee (CAC), in each of the three intervention communities, and was implemented in six phases. We conducted a process evaluation to assess implementation of each intervention component in terms of reach, dose delivered and fidelity. Implementation of each component was classified as high, medium or low according to set standards, and reported back at the end of each phase, allowing for improvements. The school and worksite components were implemented with high reach, dose delivered and fidelity, with improvement over time. The school program had only moderate reach and dose delivered, as did the social media component. The CAC achieved high reach and dose delivered. Overall, study reach and dose delivered reached a high implementation level, whereas fidelity was medium. Great challenges exist in the consistent implementation of MLMC interventions. The detailed process evaluation of the OPREVENT2 trial allowed us to carefully assess the relative strengths and limitations of each intervention component.

Association of Arsenic Exposure With Cardiac Geometry and Left Ventricular Function in Young Adults

BACKGROUND

Arsenic exposure has been related to numerous adverse cardiovascular outcomes. The aim of this study was to investigate the cross-sectional and prospective association between arsenic exposure with echocardiographic measures of left ventricular (LV) geometry and functioning.

METHODS

A total of 1337 young adult participants free of diabetes mellitus and cardiovascular disease were recruited from the SHFS (Strong Heart Family Study). The sum of inorganic and methylated arsenic concentrations in urine (ΣAs) at baseline was used as a biomarker of arsenic exposure. LV geometry and functioning were assessed using transthoracic echocardiography at baseline and follow-up.

RESULTS

Mean follow-up was 5.6 years, and median (interquartile range) of ΣAs was 4.2 (2.8-6.9) µg/g creatinine. Increased arsenic exposure was associated with prevalent LV hypertrophy, with an odds ratio (95% CI) per a 2-fold increase in ΣAs of 1.47 (1.05-2.08) in all participants and of 1.58 (1.04-2.41) among prehypertensive or hypertensive individuals. Measures of LV geometry, including LV mass index, left atrial systolic diameter, interventricular septum, and LV posterior wall thickness, were positively and significantly related to arsenic exposure. Among measures of LV functioning, stroke volume, and ejection fraction were associated with arsenic exposure.

CONCLUSIONS

Arsenic exposure was related to an increase in LV wall thickness and LV hypertrophy in young American Indians with a low burden of cardiovascular risk factors. The relationship was stronger in participants with prehypertension or hypertension, suggesting that potential cardiotoxic effects of arsenic might be more pronounced in individuals already undergoing cardiovascular adaptive mechanisms following elevated systemic blood pressure.

OPREVENT (Obesity Prevention and Evaluation of InterVention Effectiveness in NaTive North Americans): Design of a Multilevel, Multicomponent Obesity Intervention for Native American Adults and Households

Obesity prevalence is high in Native American (NA) adults, and there is a critical need to establish and implement evidence-based social, behavioral, and policy interventions that are theoretically informed. The use of multilevel, multicomponent (MLMC) interventions has been shown to be an effective strategy for comprehensive health behavior change; however, there is little guidance available in the literature to facilitate implementation in this underserved and understudied population. To decrease obesity and related comorbidities in NA adults, an MLMC intervention called OPREVENT (Obesity Prevention and Evaluation of InterVention Effectiveness in NaTive North Americans) was implemented in 5 rural NA communities to modify the food-purchasing environment, improve diet, and increase physical activity (PA). Five NA communities across the Upper Midwest and Southwest United States were randomly assigned to Immediate (n = 3) or Delayed (n = 2) Intervention. OPREVENT was implemented in Immediate Intervention community food stores, worksites, schools, and media over 1 y. A community-randomized controlled trial was used to evaluate intervention impact in adults at the individual and institutional levels, with individual-level data being collected on diet, PA, and psychosocial variables at baseline and follow-up; and institutional-level data being collected on food stores, worksites, and schools, media, and process measures. The OPREVENT intervention was one of the first MLMC obesity interventions in this population and provides evidence-based practices for future program development. The purpose of this article is to describe the design, implementation, and evaluation of OPREVENT. This trial was registered at isrctn.com as ISRCTN76144389.

Social Support and Physical Activity Among American Indians in Oklahoma: Results From a Community-based Participatory Research Study

PURPOSE

Little is known about the contribution of social support to physical activity (PA) behavior among American Indians (AIs). This community-based participatory research study examined the prevalence of and associations between different types of PA social support and PA among AIs in rural Oklahoma.

METHODS

Our tribal-academic partnership surveyed AI adults (N = 513) living within the tribal jurisdictional areas of 2 tribal nations. We used the Physical Activity Social Support (PASS) scale to assess 3 types of PA social support and Poisson regression to investigate associations between PASS types and self-reported PA behavior.

FINDINGS

Over a third of participants perceived high levels of PA social support from friends (37%), family (35%), and overall (34%), yet only 29% reported regular PA (ie, 150 minutes or more weekly). Participants who exercised with pets/other were significantly more likely to achieve regular PA than those who exercised alone (PR 2.0, 95% CI: 1.4-2.9). Although not significant, compared with those reporting no/low support, participants with high friend PASS (PR 1.2, 95%: CI 0.9-1.6), medium family PASS (PR 1.2, 95% CI: 0.9-1.7), and overall PASS (PR 1.1, 95% CI: 0.8-1.6) were more likely to report regular PA.

CONCLUSIONS

The majority of participants did not meet current recommendations for PA behavior, which underscores the ongoing need for PA effective interventions among AIs living in rural areas. Results suggest that exercising with pets/other could be an important factor for future intervention. Further research is needed to elucidate determinants of PA and test interventions to increase PA among AIs.

Targeted metabolomics to understand the association between arsenic metabolism and diabetes-related outcomes: Preliminary evidence from the Strong Heart Family Study

BACKGROUND

Inorganic arsenic exposure is ubiquitous and both exposure and inter-individual differences in its metabolism have been associated with cardiometabolic risk. A more efficient arsenic metabolism profile (lower MMA%, higher DMA%) has been associated with reduced risk for arsenic-related health outcomes. This profile, however, has also been associated with increased risk for diabetes-related outcomes.

OBJECTIVES

The mechanism behind these conflicting associations is unclear; we hypothesized the one-carbon metabolism (OCM) pathway may play a role.

METHODS

We evaluated the influence of OCM on the relationship between arsenic metabolism and diabetes-related outcomes (HOMA2-IR, waist circumference, fasting plasma glucose) using metabolomic data from an OCM-specific and P180 metabolite panel measured in plasma, arsenic metabolism measured in urine, and HOMA2-IR and FPG measured in fasting plasma. Samples were drawn from baseline visits (2001-2003) in 59 participants from the Strong Heart Family Study, a family-based cohort study of American Indians aged ≥14 years from Arizona, Oklahoma, and North/South Dakota.

RESULTS

In unadjusted analyses, a 5% increase in DMA% was associated with higher HOMA2-IR (geometric mean ratio (GMR)= 1.13 (95% CI: 1.03, 1.25)) and waist circumference (mean difference=3.66 (0.95, 6.38). MMA% was significantly associated with lower HOMA2-IR and waist circumference. After adjustment for OCM-related metabolites (SAM, SAH, cysteine, glutamate, lysophosphatidylcholine 18.2, and three phosphatidlycholines), associations were attenuated and no longer significant.

CONCLUSIONS

These preliminary results indicate that the association of lower MMA% and higher DMA% with diabetes-related outcomes may be influenced by OCM status, either through confounding, reverse causality, or mediation.

Arsenic, one carbon metabolism and diabetes-related outcomes in the Strong Heart Family Study

BACKGROUND

Inorganic arsenic exposure and inter-individual differences in its metabolism have been associated with cardiometabolic risk. A more efficient arsenic metabolism profile (lower MMA%, higher DMA%) has been associated with reduced risk for arsenic-related health outcomes; however, this profile has also been associated with increased risk for diabetes-related outcomes. The mechanism behind these contrasting associations is equivocal; we hypothesized one carbon metabolism (OCM) may play a role.

METHODS

We evaluated the association between OCM-related variables (nutrient intake and genetic variants) and both arsenic metabolism biomarkers (iAs%, MMA% and DMA%) and diabetes-related outcomes (metabolic syndrome, diabetes, HOMA2-IR and waist circumference) in 935 participants free of prevalent diabetes and metabolic syndrome from the Strong Heart Family Study, a family-based prospective cohort comprised of American Indian tribal members aged 14+ years.

RESULTS

Of the 935 participants free of both diabetes and metabolic syndrome at baseline, 279 (29.8%) developed metabolic syndrome over a median of 5.3 years of follow-up and of the 1458 participants free of diabetes at baseline, 167 (11.3%) developed diabetes over follow-up. OCM nutrients were not associated with arsenic metabolism, however, higher vitamin B₆ was associated with diabetes-related outcomes (higher HOMA2-IR and increased risk for diabetes and metabolic syndrome). A polymorphism in an OCM-related gene, methionine synthase (MTR), was associated with both higher MMA% (β = 2.57, 95% CI: 0.22, 4.92) and lower HOMA2-IR (GMR = 0.79, 95% CI = 0.66, 0.93 per 5 years of follow-up). Adjustment for OCM variables did not affect previously reported associations between arsenic metabolism and diabetes-related outcomes; however, the association between the MTR variant and diabetes-related outcomes were attenuated after adjustment for arsenic metabolism.

CONCLUSIONS

Our findings suggest MMA% may be a partial mediator in the association between OCM and diabetes-related outcomes. Additional mediation analyses with longer follow-up period are needed to confirm this finding. Further research is needed to determine whether excess B vitamin intake is associated with increased risk for diabetes-related outcomes.

The Association of Arsenic Exposure and Arsenic Metabolism With the Metabolic Syndrome and Its Individual Components: Prospective Evidence From the Strong Heart Family Study

Inorganic arsenic exposure is ubiquitous, and both exposure and interindividual differences in its metabolism have been associated with cardiometabolic risk. However, the associations of arsenic exposure and arsenic metabolism with the metabolic syndrome (MetS) and its individual components are relatively unknown. We used Poisson regression with robust variance to evaluate the associations of baseline arsenic exposure (urinary arsenic levels) and metabolism (relative percentage of arsenic species over their sum) with incident MetS and its individual components (elevated waist circumference, elevated triglycerides, reduced high-density lipoprotein cholesterol, hypertension, and elevated fasting plasma glucose) in 1,047 participants from the Strong Heart Family Study, a prospective family-based cohort study in American Indian communities (baseline visits were held in 1998-1999 and 2001-2003, follow-up visits in 2001-2003 and 2006-2009). Over the course of follow-up, 32% of participants developed MetS. An interquartile-range increase in arsenic exposure was associated with a 1.19-fold (95% confidence interval: 1.01, 1.41) greater risk of elevated fasting plasma glucose concentration but not with other individual components of the MetS or MetS overall. Arsenic metabolism, specifically lower percentage of monomethylarsonic acid and higher percentage of dimethylarsinic acid, was associated with higher risk of overall MetS and elevated waist circumference but not with any other MetS component. These findings support the hypothesis that there are contrasting and independent associations of arsenic exposure and arsenic metabolism with metabolic outcomes which may contribute to overall diabetes risk.

Findings from American Indian Needs Assessments

Because of decreased access and dismal survival rates, strategies need to be developed to increase cancer awareness and facilitate cancer prevention, early detection, and screening activities within American Indian (AI) populations. The purpose of this study was to develop a locally tailored needs assessment to collect cancer prevention, control, and risk factor information and knowledge, attitude, and perceived behavior (hereafter referred to as "needs assessment") data from 500 community members living in 3 geographically diverse settings: the Southeastern USA, the Rocky Mountain region, and the Northern Plains. Needs assessment data helped identify local health priorities and create a pilot cancer prevention and early detection education intervention. There were two versions of common items of the instrument: short (~35 items) and long (55 items), and each partner added items that were recommended by their local AI Advisory Committee. Each partner collaborated with local AI organizations to identify and recruit participants at community venues. During the sessions, facilitators used Power Point® slides and ARS equipment and software to anonymously collect participants' responses. The partners collected needs assessment data from 677 community members over a 4-year period. Cancer education knowledge was low, barriers to accessing timely cancer screening and care services were excessive, tobacco use was excessive, and daily physical activity was insufficient for most participants. ARS was an effective way to collect needs assessment information. During discussions following the data collection, community members requested more cancer education opportunities, access to patient navigation services, and cultural competency training for healthcare providers.

OPREVENT2: Design of a multi-institutional intervention for obesity control and prevention for American Indian adults

Background

Obesity and other nutrition-related chronic disease rates are high in American Indian (AI) populations, and an urgent need exists to identify evidence-based strategies for prevention and treatment. Multi-level, multi-component (MLMC) interventions are needed, but there are significant knowledge gaps on how to deliver these types of interventions in low-income rural AI communities.

Methods

OPREVENT2 is a MLMC intervention targeting AI adults living in six rural reservations in New Mexico and Wisconsin. Aiming to prevent and reduce obesity in adults by working at multiple levels of the food and physical activity (PA) environments, OPREVENT2 focuses on evidence-based strategies known to increase access to, demand for, and consumption of healthier foods and beverages, and increase worksite and home-based opportunities for PA. OPREVENT2 works to create systems-level change by partnering with tribal stakeholders, multiple levels of the food and PA environment (food stores, worksites, schools), and the social environment (children as change agents, families, social media). Extensive evaluation will be conducted at each level of the intervention to assess effectiveness via process and impact measures.

Discussion

Novel aspects of OPREVENT2 include: active engagement with stakeholders at many levels (policy, institutional, and at multiple levels of the food and PA system); use of community-based strategies to engage policymakers and other key stakeholders (community workshops, action committees); emphasis on both the built environment (intervening with retail food sources) and the social environment. This paper describes the design of the intervention and the evaluation plan of the OPREVENT2.

Trial registration

Clinical Trial Registration: NCT02803853 (June 10, 2016)

Tai Chi’s Effects on Health-Related Fitness of Low-Income Older Adults

On a démontré que le Tai Chi peut influer positivement sur la condition physique liée à la santé (CLPS) des participants âgés, en leur offrant un moyen d’accoître la force musculo-squelettique. L’objectif de cette étude était d’examiner les effets de l’intervention de Tai Chi sur la forme physique, et de découvrir si ethnies culturellement étrangères au Tai Chi constituaient un obstacle à la participation à un programme communautaire pour les aînés à faible revenu. Soixante-dix-huit aînés d’origine mixte (55 ans et plus), qui n’étaient pas culturellement affiliés au Tai Chi, ont été recrutés pour cette étude. Les mesures de la condition liée à la santé ont été prises avant et après un programme de Tai Chi d’une durée de 16 semaines, avec sept séances par semaine. Des améliorations significatives en résultaient dans l’aptitude supérieur et inférieur musculo-squelettique ainsi que dans la flexion partielle parmi ceux qui pratiquaient le Tai Chi. Ces résultats suggèrent que le Tai Chi peut être efficace pour améliorer la CLPS, et que les ethnies non pas liées culturellement au Tai Chi n’éprouviaent pas un obstacle à la participation d’un échantillon de population âgée à un niveau socio-économique faible.

Differences in risk factors for coronary heart disease among diabetic and nondiabetic individuals from a population with high rates of diabetes: the Strong Heart Study

CONTEXT

Coronary heart disease (CHD) is the leading cause of death in the United States.

OBJECTIVE

This study compares differences in risk factors for CHD in diabetic vs. nondiabetic Strong Heart Study participants.

DESIGN

This was an observational study.

SETTING

The study was conducted at three centers in Arizona, Oklahoma, and North and South Dakota.

PARTICIPANTS

Data were obtained from 3563 of 4549 American Indians free of cardiovascular disease at baseline.

INTERVENTION(S)

CHD events were ascertained during follow-up.

MAIN OUTCOME MEASURE

CHD events were classified using standardized criteria.

RESULTS

In diabetic and nondiabetic participants, 545 and 216 CHD events, respectively, were ascertained during follow-up (21,194 and 22,990 person-years); age- and sex-adjusted incidence rates of CHD were higher for the diabetic group (27.5 vs. 12.1 per 1,000 person-years). Risk factors for incident CHD common to both groups included older age, male sex, prehypertension or hypertension, and elevated low-density lipoprotein cholesterol. Risk factors specific to the diabetic group were lower high-density lipoprotein cholesterol, current smoking, macroalbuminuria, lower estimated glomerular filtration rate, use of diabetes medication, and longer duration of diabetes. Higher body mass index was a risk factor only for the nondiabetic group. The association of male sex and CHD was greater in those without diabetes than in those with diabetes.

CONCLUSIONS

In addition to higher incidence rates of CHD events in persons with diabetes compared with those without, the two groups differed in CHD risk factors. These differences must be recognized in estimating CHD risk and managing risk factors.

Physical activity and fruit and vegetable intake among American Indians

The American Indian population has among the highest rates of obesity in the United States. Thus, it is critical to understand factors related to this epidemic (e.g., physical activity, nutrition) among this ethnic minority population. The current study examined factors related to engaging in at least 4 days of physical activity (PA) per week and factors related to consuming at least 5 fruits and vegetables (FV) per day among a sample of American Indians in the Midwest. We used multiple methods to recruit participants for this study, including recruitment at pow wows, focus groups, health fairs, new student orientation for American Indian students, and other venues. A total of 998 American Indians (76% participation rate) completed a survey assessing sociodemographics, physical activity level, fruit and vegetable intake, and perceptions regarding the recommendations for physical activity and fruit and vegetable intake. Factors associated with exercising ≥4 days in the past week (44.77% of the sample) include being younger (P = .002), being male (P < .001), having at least some college education (P = .048), eating ≥5 FV per day, and higher perceived number of days of PA recommended (P < .001). Factors associated with eating ≥5 servings of FV per day (37.01% of the sample) included exercising ≥4 days in the past week (P < .001) and higher perceived number of servings of FV recommended (P < .001). These findings highlight the importance of education in enhancing engagement in positive weight control behaviors and the importance of addressing both physical activity and nutrition among the American Indian population.

Hemoglobin A1c, fasting glucose, and cardiovascular risk in a population with high prevalence of diabetes: the strong heart study

OBJECTIVE

We compared A1C and fasting plasma glucose (FPG) in predicting cardiovascular disease (CVD) in a population with widespread obesity and diabetes.

RESEARCH DESIGN AND METHODS

A total of 4,549 American Indian adults underwent the Strong Heart Study (SHS) baseline examination (1989-1991). Data from 3,850 individuals (60% women) with baseline measurements of FPG and A1C and no prevalent CVD were analyzed; 1,386 had known diabetes. CVD events were ascertained over a median of 15 years.

RESULTS

A1C ≥6.5% had a 44.3% sensitivity and 98.9% specificity to identify participants with FPG ≥126 mg/dL. Increases in A1C were associated with adverse CVD risk factor profiles; individuals with known diabetes had worse profiles. For A1C <5, 5 to <5.5, 5.5 to <6, 6-6.5, or ≥6.5% or known diabetes, the multivariate-adjusted hazard ratio (HR) [95% CI] for coronary heart disease (CHD) was significant only for individuals with known diabetes (2.76 [2.17-3.51]). Similarly, the adjusted HRs for total CVD were significant only for individuals with A1C ≥6.5% or known diabetes (1.50 [1.10-2.04] and 2.52 [2.06-3.08], respectively). Similar results were observed for FPG.

CONCLUSIONS

Individuals with known or newly diagnosed diabetes had increased risk for CVD. Although A1C is more convenient than FPG in diagnosing diabetes, neither test adds to conventional CVD risk factors in predicting CHD or total CVD.

Incidence rates and predictors of diabetes in those with prediabetes: the Strong Heart Study

BACKGROUND

The association between prediabetes as currently defined and incident diabetes in populations with widespread obesity, insulin resistance syndrome, and diabetes is not well defined. In this article, diabetes risk factors and incidence rates in American Indians (AI) with prediabetes are examined.

METHODS

A total of 1677 AI who were nondiabetic at baseline was examined during a median 7.8-year follow-up as part of the Strong Heart Study (SHS). Risk factors for incident diabetes were measured. Prediabetes was defined according to American Diabetes Association 2003 criteria as having impaired glucose tolerance (IGT) (2-h plasma glucose [2-h PG] >or= 140 mg/dL but < 200 mg/dL) and/or impaired fasting glucose (IFG) (fasting plasma glucose [FPG] >or= 100 mg/dL but < 126 mg/dL).

RESULTS

Prediabetes was identified by FPG alone in 87.5%. Diabetes incidence in those with baseline prediabetes was 66.1/1000 person-years, with a hazard ratio (HR) of 2.35 (95% conference interval: 1.84-3.01), compared with participants with normal glucose tolerance (NGT) at baseline. Elevated A(1c), 2-h PG, and fasting insulin (FI); albuminuria; and obesity were significantly associated with conversion from prediabetes to diabetes. Younger age, elevated FI (or body mass index [BMI] in models without FI), and less physical activity were significantly associated with conversion from NGT.

CONCLUSIONS

Prediabetes is an independent predictor of conversion to type 2 diabetes in AI, and most can be identified through a fasting glucose measure. Measures of obesity, A(1c), FPG, 2-h PG, FI, albuminuria, and insulin resistance (IR) help predict this conversion. Obesity is a modifiable risk factor. Strategies to reduce obesity should be emphasized in individuals with prediabetes.

Alaskan wild berry resources and human health under the cloud of climate change

Wild berries are integral dietary components for Alaska Native people and a rich source of polyphenolic metabolites that can ameliorate metabolic disorders such as obesity and diabetes. In this study, five species of wild Alaskan berries (Vaccinium ovalifolium , Vaccinium uliginosum , Rubus chamaemorus , Rubus spectabilis , and Empetrum nigrum) were screened for bioactivity through a community-participatory research method involving three geographically distinct tribal communities. Compositional analysis by HPLC and LC-MS(2) revealed substantial site-specific variation in anthocyanins (0.01-4.39 mg/g of FW) and proanthocyanidins (0.74-6.25 mg/g of FW) and identified A-type proanthocyanidin polymers. R. spectabilis increased expression levels of preadipocyte factor 1 (182%), and proanthocyanidin-enriched fractions from other species reduced lipid accumulation in 3T3-L1 adipocytes. Selected extracts reduced serum glucose levels in C57BL/6J mice by up to 45%. Local observations provided robust insights into effects of climatic fluctuations on berry abundance and quality, and preliminary site-specific compositional and bioactivity differences were noted, suggesting the need to monitor this Alaska Native resource as climate shifts affect the region.

Diabetes and incident heart failure in hypertensive and normotensive participants of the Strong Heart Study

OBJECTIVES

Type 2 diabetes is accepted as a cause of heart failure, but direct cause-effect evidence independent of incident myocardial infarction (MI), hypertension and other coexisting risk factors is less well studied. We tested the hypothesis that diabetes predisposes to heart failure independently of hypertension and intercurrent MI.

METHODS

We evaluated 12-year incident heart failure in 2740 participants (1781 women) without prevalent cardiovascular or severe kidney disease, at the time of the first exam of the Strong Heart Study cohort. Intercurrent MI was censored as a competing risk event.

RESULTS

Diabetes was present in 1206 individuals (44%), and impaired fasting glucose (IFG) in 391 (14%). Diabetic participants more frequently had hypertension and/or central obesity (both P < 0.0001). Incident heart failure was ascertained in 64 participants with normal fasting glucose (NFG; 6%), 26 (7%) with IFG and 201 with diabetes (17%, hazard ratio = 4.04 vs. NFG, P < 0.0001). In Cox analysis adjusting for age, sex, obesity, central fat distribution, hypertension, antihypertensive medications, prevalent atrial fibrillation, glomerular filtration rate, urinary albumin/creatinine ratio, plasma cholesterol, Hb1Ac, smoking habit, alcohol use, educational level and physical activity, diabetes was associated with a two-fold greater risk of incident heart failure than NFG (hazard ratio = 2.45, P < 0.0001). Diabetes maintained 1.5-fold greater risk of heart failure than NFG (P < 0.03) even when intercurrent MI (n = 221) was censored as a competing risk event, similar to the adjusted hazard ratio for heart failure in hypertension.

CONCLUSION

Type 2 diabetes is a potent, independent risk factor for heart failure. Risk of heart failure in diabetic patients cannot be fully explained by incident MI and coexisting cardiovascular risk factors. Mechanisms directly related to diabetes and impairing cardiac function should be studied and identified.

Epidemiology of physical activity in American Indians in the Education and Research Towards Health cohort

BACKGROUND

The health benefits of an active lifestyle are well established. However, Americans in general and American Indians specifically are not sufficiently active to achieve these health benefits.

PURPOSE

This study presents the descriptive epidemiology of physical activity in a community-based sample of American-Indian adults.

METHODS

Data came from Education and Research Towards Health (EARTH), a cross-sectional study conducted between December 2003 and April 2006 of 5207 American-Indian adults in South Dakota and Arizona. Physical activity was assessed using a culturally tailored, computer-assisted instrument. Both type and intensity of activities were measured; minutes per week averaged over the past year was the primary outcome. Individuals were categorized as being sufficiently active, not sufficiently active, or inactive using a cut point of more or less than 150 minutes/week. Information on age, gender, and BMI was also collected.

RESULTS

More than one third of participants were not sufficiently active (<150 minutes/week) and 18% reported no leisure-time activity. Sufficient activity was less often reported by women than men (41% vs 56%) and by participants from the Southwest than those from the Northern Plains (44% vs 50%). Of all activity categories, the most time was spent on household activities among all participants. There were clear trends in physical (in)activity across BMI strata; time spent in sedentary activities increased while leisure-time activity decreased with BMI.

CONCLUSIONS

American-Indian adults in this cohort exhibited levels of physical (in)activity similar to those of other racial/ethnic groups in the U.S., suggesting a need for specific interventions to increase activity levels across the population.

Physical activity and incident diabetes in American Indians: the Strong Heart Study

The authors examined the association between total physical activity (leisure-time plus occupational) and incident diabetes among 1,651 American Indians who participated in the Strong Heart Study, a longitudinal study of cardiovascular disease and its risk factors among 13 American Indian communities in 4 states (North Dakota, South Dakota, Oklahoma, and Arizona). Discrete Cox models were used to examine the association between physical activity level (in tertiles), compared with no physical activity, and incident diabetes, after adjustment for potential confounders. During 10 years of follow-up (f1989-1999), 454 incident cases of diabetes were identified. Compared with participants who reported no physical activity, those who reported any physical activity had a lower risk of diabetes: Odds ratios were 0.67 (95% confidence interval (CI): 0.46, 0.99), 0.67 (95% CI: 0.45, 0.99), and 0.67 (95% CI: 0.45, 0.99) for increasing tertile of physical activity, after adjustment for age, sex, study site, education, smoking, alcohol use, and family history of diabetes. Further adjustment for body mass index and other potential mediators attenuated the risk estimates. These data suggest that physical activity is associated with a lower risk of incident diabetes in American Indians. This study identifies physical activity as an important determinant of diabetes among American Indians and suggests the need for physical activity outreach programs that target inactive American Indians.

Physical activity patterns of American Indian and Alaskan Native people living in Alaska and the Southwestern United States

PURPOSE

Assessment of self-reported physical activity (PA) and effects on health measures.

DESIGN

Cross-sectional analysis of baseline data from a cohort study.

SETTING

Education and Research Towards Health study participants from Alaska and the Southwestern United States enrolled from 2004 to 2007.

SUBJECTS

Total of 10,372 American Indian and Alaskan Native people (AI/AN) of at least 18 years.

MEASURES

Participants completed computer-assisted, self-administered questionnaires, and anthropometric and health measurements were taken of each participant.

ANALYSIS

Analysis of variance, chi2 tests, and multiple linear regressions were used.

RESULTS

Almost 23% of participants reported less than 30 minutes per week of moderate or vigorous activities. Half (49%) reported no vigorous activities. Characteristics associated with more time spent performing vigorous activity were male gender, age less than 40 years, higher income and education levels, and living in a rural area. Almost 70% of Alaskan participants and 36% of Southwest participants engaged in wild food-harvesting activities. Participants with higher levels of activity had significantly better clinical characteristics (high-density lipoprotein cholesterol, triglycerides, body mass index, and waist circumference).

CONCLUSION

AI/AN people engage in many different physical activities, including traditional harvesting activities. Women had lower levels of PA than men, and participation in vigorous PA was associated with better clinical characteristics. These data can be used to guide health promotion efforts in AI/AN populations.

[Physical activity among aboriginals in Canada]

This paper summarizes available information on patterns of physical activity, their determinants and consequences, and the results of various interventions designed to increase the physical activity of Aboriginal peoples in Canada and the United States. There is a paucity of national data on this issue for Aboriginal peoples. The most recent data, from the First Nations Regional Longitudinal Health Survey of 2002-2003, indicate that 21% of adults (27% of men, 15% of women) were engaging in at least 30 min of moderate to vigorous physical activity on 4 d/week or more. The present paper highlights the unique challenges this group faces, underlining the need to integrate collective knowledge regarding how much physical activity is required for Aboriginal Canadians, and how this activity should be accomplished, to promote and maintain health. Efforts are currently underway to tailor Canada's physical activity guide for First Nations, Inuit, and Métis. Future research among Aboriginal groups should examine the minimal and optimal levels of physical activity required to achieve health benefits.

Incidence and risk factors for stroke in American Indians: the Strong Heart Study

BACKGROUND

There are few published data on the incidence of fatal and nonfatal stroke in American Indians. The aims of this observational study were to determine the incidence of stroke and to elucidate stroke risk factors among American Indians.

METHODS AND RESULTS

This report is based on 4549 participants aged 45 to 74 years at enrollment in the Strong Heart Study, the largest longitudinal, population-based study of cardiovascular disease and its risk factors in a diverse group of American Indians. At baseline examination in 1989 to 1992, 42 participants (age- and sex-adjusted prevalence proportion 1132/100 000, adjusted to the age and sex distribution of the US adult population in 1990) had prevalent stroke. Through December 2004, 306 (6.8%) of 4507 participants without prior stroke suffered a first stroke at a mean age of 66.5 years. The age- and sex-adjusted incidence was 679/100 000 person-years. Nonhemorrhagic cerebral infarction occurred in 86% of participants with incident strokes; 14% had hemorrhagic stroke. The overall age-adjusted 30-day case-fatality rate from first stroke was 18%, with a 1-year case-fatality rate of 32%. Age, diastolic blood pressure, fasting glucose, hemoglobin A(1c,) smoking, albuminuria, hypertension, prehypertension, and diabetes mellitus were risk factors for incident stroke.

CONCLUSIONS

Compared with US white and black populations, American Indians have a higher incidence of stroke. The case-fatality rate for first stroke is also higher in American Indians than in the US white or black population in the same age range. Our findings suggest that blood pressure and glucose control and smoking avoidance may be important avenues for stroke prevention in this population.

The metabolic syndrome in American Indians: the strong heart study

Although the underlying cause of the metabolic syndrome (MS) is not entirely clear, it is thought that MS results from central obesity and insulin resistance (IR). IR has long been known to be a predictor of type 2 diabetes in many populations, including American Indians, the group with a rising prevalence of obesity and the highest rate of diabetes in the United States. In addition to being a predictor of diabetes, MS has now been shown to be associated with higher risk of cardiovascular disease, independent of diabetes, in American Indians as well as in other ethnic groups. Furthermore, MS may carry a risk beyond that of single risk factors. Identifying MS in American Indians and treating the factors that comprise it may reduce risk of both diabetes and cardiovascular disease in this population.

Association of physical activity with sleep-disordered breathing

This study was performed to determine whether there is a protective association between participation in vigorous or vigorous/moderately vigorous physical activity and the prevalence of sleep-disordered breathing (SDB). Polysomnographic and questionnaire data from the baseline examination of 4,275 participants in the Sleep Heart Health Study (SHHS) were analyzed in relation to information on amount of physical activity and other potentially relevant factors collected from five SHHS parent cohorts (Atherosclerosis Risk in Communities Study, Cardiovascular Health Study, Framingham Heart Study, Strong Heart Study, and Tucson Epidemiologic Study of Airways Obstructive Diseases). Logistic regression models were fitted to determine if amount and strenuousness of physical activity was associated with the presence of SDB. At least 3 h per week of vigorous physical activity reduced the odds of SDB, defined as a respiratory disturbance index (RDI) of at least 15 apneas/hypopneas per hour (Adjusted OR, 0.68; 95%CI, 0.51-0.91). A qualitatively similar but slightly weaker association was observed when SDB was defined as a RDI > or = 10 per hour (Adjusted OR, 0.81; 95%CI, 0.64-1.02). These findings remained after adjustment for sleepiness and restricting analyses to participants with good health. Three or more hours of moderately vigorous or vigorous physical activity also appeared to confer some protection against SDB, but these associations were weaker. Gender- and obesity-stratified analyses suggested that the protective association between physical activity and SDB occurred primarily in men and those who were obese. A program of regular vigorous physical activity of at least 3 h per week may be a useful adjunctive treatment modality for SDB, but this association needs confirmation with a prospective clinical trial.

Physical activity of Aboriginal people in CanadaThis article is part of a supplement entitled Advancing physical activity measurement and guidelines in Canada: a scientific review and evidence-based foundation for the future of Canadian physical activity guidelines co-published by Applied Physiology, Nutrition, and Metabolism and the Canadian Journal of Public Health. It may be cited as Appl. Physiol. Nutr. Metab. 32(Suppl. 2E) or as Can. J. Public Health 98(Suppl. 2)

This paper summarizes available information on patterns of physical activity, their determinants and consequences, and the results of various interventions designed to increase the physical activity of Aboriginal peoples in Canada and the United States. There is a paucity of national data on this issue for Aboriginal peoples. The most recent data, from the First Nations Regional Longitudinal Health Survey of 2002–2003, indicate that 21% of adults (27% of men, 15% of women) were engaging in at least 30 min of moderate to vigorous physical activity on 4 d/week or more. The present paper highlights the unique challenges this group faces, underlining the need to integrate collective knowledge regarding how much physical activity is required for Aboriginal Canadians, and how this activity should be accomplished, to promote and maintain health. Efforts are currently underway to tailor Canada’s physical activity guide for First Nations, Inuit, and Métis. Future research among Aboriginal groups should examine the minimal and optimal levels of physical activity required to achieve health benefits.

Macronutrient intake and glycemic control in a population-based sample of American Indians with diabetes: the Strong Heart Study

BACKGROUND

Little research has explored the association of macronutrient intake and glycated hemoglobin (HbA(1c)) in adults with diabetes.

OBJECTIVE

The objective of the study was to examine the cross-sectional association between macronutrient intake and HbA(1c) in diabetic American Indians.

DESIGN

A total of 1284 participants aged 47-80 y who had diabetes for >or=1 y at the second examination (1993-1995) of the Strong Heart Study were included in this study. Dietary intake was assessed by using a 24-h recall. Logistic regression models were used to evaluate the odds of poor glycemic control (HbA(1c) >or= 7%) among sex-specific quintiles of macronutrient intake, after adjustment for the possible confounders age, sex, study center, body mass index, duration of diabetes, diabetes treatment, smoking, alcohol drinking, total energy intake, and physical activity.

RESULTS

Higher total fat (>25-30% of energy), saturated fatty acids (>13% of energy), and monounsaturated fatty acids (>10% of energy) and lower carbohydrate intake (<35-40% of energy) were associated with poor glycemic control. Lower fiber intake and higher protein intake were marginally associated with poor glycemic control (P for trend = 0.06 and 0.09, respectively). No significant association was found between polyunsaturated fatty acids or trans fatty acids and glycemic control in this population.

CONCLUSIONS

These data suggest that a higher consumption of total fat and saturated and monounsaturated fatty acids and a lower intake of carbohydrates are associated with poor glycemic control in diabetic American Indians. Clinical trials focusing on whether modifications of macronutrient composition improve glycemic control in persons with diabetes are needed.

Dietary calcium is associated with body mass index and body fat in American Indians

American Indians have a high prevalence of obesity. Evidence supports a relationship between increased dietary calcium intake and lower body weight. This study was conducted to investigate the association between dietary calcium intake, BMI, and percentage of body fat (PBF) in American Indians (ages 47-79 y) in the Strong Heart Study (SHS) (2nd exam, 1992-1995). SHS data were compared with data for the general U.S. adult population from the NHANES III (1988-1994). BMI was calculated as kg/m(2). PBF was estimated by bioelectrical impedance using an equation based on total body water. The clinical examination included measures of blood chemistry. Dietary data were collected using a 24-h dietary recall. Calcium intake was significantly lower in SHS participants than in age-matched NHANES III participants. Mean calcium intake in the SHS was 680 mg/d (range: 103-4574 mg/d) for men and 610 mg/d (range: 71-4093 mg/d) for women (P < 0.001). After adjustment for potential confounders, BMI and PBF were lower by 0.80 kg/m(2) (95% CI: -1.53 to -0.08, P = 0.046) and 1.28% (95% CI: -2.10 to -0.47, P = 0.011) in SHS participants with higher (> or = 873 mg/d in the 5th quintile) vs. lower calcium intake (<313 mg/d in the 1st quintile). No relation between calcium intake and BMI or PBF was observed in NHANES III participants. Our data may be used to develop nutritional interventions aimed at weight control in culturally appropriate clinical trials.

The nutrition transition in American Indians

The purpose of this article was to examine whether a nutritional transition has occurred among American Indians (AI) by evaluating related articles and government health statistics. Findings indicate that although the primary health risk for the AI population around 1970 was undernutrition, now there is an obesity epidemic among all age groups that is associated with a loss of traditional food practices and reduced physical activity. Deaths caused by cardiovascular disease, diabetes mellitus, and cancer have outpaced death from infectious disease. With abundant high-energy foods and limited physical activity, the acculturated environment has resulted in obesity and increased mortality from chronic diseases. To improve AI health and survival, the obesity epidemic must be approached in a concerted, culturally appropriate manner with encouragement of traditional foods and safe opportunities for physical activity.

Physical activity and Native Americans: a review

The physical activity behaviors of Native-American populations in the United States and Canada have received little attention in the health literature. The purpose of this review was to unite the literature regarding the physical activity behaviors of Native Americans. A majority of the literature was obtained using online databases. Reference lists were also reviewed to gain further access to the literature. Key-word searches included various combinations of Aboriginal, Native Indian, American Indian, Native American, First Nation, Métis, or Alaska Native with physical activity, exercise, and health behavior. Articles included were those published in English-language, peer-reviewed journals from 1990 until November 2005 that focused on participants aged 18 years and older. This review is organized according to ecologic models of health behavior, which take into account several correlates to explain human behavior, including demographic, personal health, environmental, and psychosocial. Correlates were included if they appeared at least three times in the literature. As a result of these inclusion criteria, the number of reviewed articles includes 28 quantitative, 4 qualitative, and 3 intervention studies. Results indicate that age, gender, and social support are important factors associated with physical activity. The remaining correlates show inconsistent or indeterminate results due in part to the paucity of research. It is suggested that an increase in the number of studies, especially those using longitudinal designs, is needed. Further, the application of psychosocial models to understand physical activity motivations as well as culturally appropriate and validated measurement tools are largely absent in the Native-American physical activity literature.

Plasma lipoprotein concentrations in ethnic populations

There is a complex interplay between genetic and environmental factors that influences the expression of plasma lipoprotein levels. It is therefore not surprising that differences in lipid levels have been reported between ethnic groups. There are conflicting data on racial and ethnic variations in lipids, and also limited data on the relationship between lipoprotein levels and coronary heart disease risk in specific populations. This review summarizes available data on ethnic variations in plasma lipoproteins and the potential impact on coronary morbidity and mortality.

Evidence for joint action of genes on diabetes status and CVD risk factors in American Indians: the strong heart family study

OBJECTIVES

Previous research among American Indians of the strong heart family study (SHFS) has demonstrated significant heritabilities for CVD risk factors and implicated diabetes as an important predictor of several of the phenotypes. Moreover, we recently demonstrated that genetic effects on CVD risk factors differed in diabetic and nondiabetic individuals. In this paper, we investigated whether a significant genetic influence on diabetes status could be identified, and whether there is evidence for joint action of genes on diabetes status and related CVD risk factors.

METHODS AND RESULTS

Approximately 950 men and women, age 18 or older, in 32 extended families, were examined between 1997 and 1999. We estimated the effects of genes and environmental covariates on diabetes status using a threshold model and a maximum likelihood variance component approach. Diabetes status exhibited a residual heritability of 22% (h2=0.22). We also estimated the genetic and environmental correlations between diabetes susceptibility and eight risk factors for CVD. All eight CVD risk factors displayed significant genetic correlations with diabetes status (BMI (rhoG=0.55), fibrinogen (rhoG=0.40), HDL-C (rhoG=-0.37), ln triglycerides (rhoG=0.65), FAT (rhoG=0.38 ), PAI-1 (rhoG=0.67), SBP (rhoG=0.57), and WHR (rhoG=0.58)). Three of eight traits (HDL-C (rhoE=-0.32), ln triglycerides (rhoE=0.33), and fibrinogen (rhoE=0.20)) displayed significant environmental correlations with diabetes status.

CONCLUSIONS

These findings suggest that in the context of a high prevalence of diabetes, still unidentified diabetes genes may play an important role in influencing variation in CVD risk factors.

Environmental, policy, and cultural factors related to physical activity in African American women

Six focus groups were conducted in South Carolina with African American women (n = 42) aged 19-51 years to identify factors that influence physical activity. Transcripts were analyzed using NUD*IST. Cultural influences were seen as more important in determining the type of physical activity than its level. Barriers to and enablers of physical activity were identified in the social and physical environments, as were policy issues affecting physical activity in the community and at the work site. Potential community and work site interventions were suggested. Child care and monetary costs were frequently cited as barriers to physical activity.

Alcohol intake and glycemia in American Indians: the strong heart study

The goal of this study was to explore the relationship between alcohol intake and glycemia and type 2 diabetes in American Indians aged 45 to 74 years. Data were obtained from participants in the Strong Heart Study, a longitudinal study of 13 American Indian communities in 3 geographic areas in the United States. Alcohol consumption was determined by self-reported alcohol intake history. Participants previously diagnosed with diabetes were excluded from the analysis. Analysis of covariance (ANCOVA) was used to estimate the adjusted means of blood glucose for alcohol intake categories. Logistic regression was used to calculate the odds ratios (ORs) and 95% confidence intervals (CIs) to estimate the association between alcohol intake and type 2 diabetes in the cross-sectional analysis and between alcohol intake and glucose intolerance using longitudinal data. Fasting and 2-hour plasma glucose concentrations showed an inverse J-shaped curve across categories of alcohol intake. Using never drinkers as the referent group in cross-sectional analysis, light drinkers had a significantly lower risk of having diabetes (OR, 0.66; 95% CI, 0.44 to 0.99); among drinkers, heavy drinkers had a higher, although not significant, prevalence of diabetes. Longitudinal analysis showed no significant worsening of glucose tolerance across levels of alcohol intake. Subanalyses stratified by body mass index (BMI) did not show differences between obese and non-obese participants in the relationship between alcohol intake and glucose tolerance. Although plasma glucose concentration showed a shallow, inverse J-shaped association across levels of increasing alcohol intake in American Indians aged 45 to 74 years, alcohol intake did not appear to significantly increase the risk for worsening glucose tolerance. Thus, alcohol intake does not appear to be a determinant of diabetes risk in this population.

Sociodemographic diversity and behavioral medicine

The broad array of economic and cultural diversity in the U.S. population correlates with and impacts on the study of behavioral aspects of health. The purpose of this article was to provide a selective overview of behavioral medicine research on sociodemographically diverse populations, with a focus on ethnicity, gender, and socioeconomic status. Suggestions are provided with regard to methodological refinement of research and insights into possible future directions in behavioral medicine research on ethnically and economically diverse populations.

Changes in cardiovascular disease risk factors among American Indians. The Strong Heart Study

PURPOSE

This study describes changes in cardiovascular disease (CVD) risk factors in older American Indians over a 4-year period.

METHODS

The Strong Heart Study, a longitudinal population-based study of CVD and CVD risk factors among American Indians aged 45-74 years, measured CVD risk factors among 3638 members of 13 tribes in three geographic areas during examinations in 1989 to 1991 and 1993 to 1995.

RESULTS

Changes in mean low-density lipoprotein (LDL) cholesterol and the prevalence of elevated LDL cholesterol were inconsistent. Mean high- density lipoprotein (HDL) cholesterol decreased, and the prevalence of low HDL cholesterol increased throughout. Mean systolic blood pressure and hypertension rates increased in nearly all center-sex groups, and hypertension awareness and treatment improved. Smoking rates decreased but remained higher than national rates except among Arizona women. Mean weight and percentage body fat decreased in nearly all center-sex groups but the prevalence of obesity did not change significantly in any group. Diabetes and albuminuria prevalence rates increased throughout the study population. The prevalence of alcohol use decreased, but binge drinking remained common in those who continued to drink.

CONCLUSIONS

Improvements in management and prevention of hypertension, diabetes, renal disease, and obesity, and programs to further reduce smoking and alcohol abuse, are urgently needed.

Interventions to promote physical activity by older adults

Physical inactivity has been established to be an independent risk factor for a range of chronic diseases and conditions that threaten the health of the nation. However, only a minority of the population is currently meeting the recommended levels of regular physical activity, which have been linked with important health and quality-of-life benefits. Older adults are at particular risk for leading sedentary lifestyles. This article provides an overview of factors associated with physical activity for older adults and also describes potentially promising interventions for promoting regular physical activity in this growing population segment. Examples of interventions undertaken at personal and interpersonal as well as broader levels of analysis (e.g., environmental) are provided. Major issues currently facing the field are discussed, including the ongoing challenge of developing assessment tools that are sensitive to the more moderate-intensity physical activities favored by older adults and the formidable task of combining clinical approaches with environmental and policy strategies aimed at combating this public health problem.

Effects of obesity and body fat distribution on lipids and lipoproteins in nondiabetic American Indians: The Strong Heart Study

OBJECTIVES

To examine the relationship between obesity and lipoprotein profiles and compare the effects of total obesity and central adiposity on lipids/lipoproteins in American Indians.

RESEARCH METHODS AND PROCEDURES

Participants were 773 nondiabetic American Indian women and 739 men aged 45 to 74 years participating in the Strong Heart Study. Total obesity was estimated using body mass index (BMI). Central obesity was measured as waist circumference. Lipoprotein measures included triglycerides, high-density lipoprotein (HDL) cholesterol, low-density lipoprotein (LDL) cholesterol, apolipoprotein AI (apoAI), and apolipoprotein B (apoB). Partial and canonical correlation analyses were used to examine the associations between obesity and lipids/ lipoproteins.

RESULTS

Women were more obese than men in Arizona (median BMI 32.1 vs. 29.2 kg/m2) and South Dakota and North Dakota (28.3 vs. 28.0 kg/m2), but there was no sex difference in waist circumference. Men had higher apoB and lower apoAI levels than did women. In women, when adjusted for center, gender, and age, BMI was significantly related to HDL cholesterol (r = -0.24, p < 0.001). There was a significant but weak relation with apoAI (r = -0.14, p < 0.001). Waist circumference was positively related to triglycerides (r = 0.14, p < 0.001) and negatively related to HDL cholesterol (r = -0.23, p < 0.001) and apoAI (r = -0.13, p < 0.001). In men, BMI was positively correlated with triglycerides (r = 0.30, p < 0.001) and negatively correlated with HDL cholesterol (r = -0.35, p < 0.001) and apoAI (r = -0.23, p < 0.001). Triglycerides increased with waist circumference (r = 0.30, p < 0.001) and HDL cholesterol decreased with waist circumference (r = -0.36, p < 0.001). In both women and men there was an inverted U-shaped relationship between obesity and waist with LDL cholesterol and apoB. In canonical correlation analysis, waist circumference received a greater weight (0.86) than did BMI (0.17) in women. However, the canonical weights were similar for waist (0.46) and BMI (0.56) in men. Only HDL cholesterol (-1.02) carried greater weight in women, whereas in men, triglycerides (0.50), and HDL cholesterol (-0.64) carried a large amount of weight. All the correlation coefficients between BMI, waist circumference, and the first canonical variable of lipids/lipoproteins or between the individual lipid/lipoprotein variables and the first canonical variable of obesity were smaller in women than in men. Triglycerides and HDL cholesterol showed clinically meaningful changes with BMI and waist circumference in men. All lipid/lipoprotein changes in women in relation to BMI and waist circumference were minimal.

DISCUSSION

The main lipoprotein abnormality related to obesity in American Indians was decreased HDL cholesterol, especially in men. Central adiposity was more associated with abnormal lipid/lipoprotein profiles than general obesity in women; both were equally important in men.

Self-administered questionnaire compared with interview to assess past-year physical activity

PURPOSE

The Modifiable Activity Questionnaire (MAQ) is a physical activity questionnaire shown to be both valid and reliable and was initially designed to be interviewer-administered. After translation and adaptation into French, the objective of the study was to compare past-year physical activity data obtained by self-administration of this questionnaire and by interviewer-administration.

METHODS

84 subjects (22 men, 62 women, age 36-63 yr) enrolled in an ongoing prospective study in France (the SUpplementation en VItamines et Minéraux AntioXydants or SU.VI.MAX study) completed both versions of the questionnaire in a randomized order with a mean (SD) delay of 7.9 (5.8) d between the two modes. Past-year leisure and occupational physical activity were expressed as both h x wk(-1) and MET-h x wk(-1) of activity, and television watching was expressed as h x d(-1). Analysis of variance on ranks was used to compare activity variables obtained by self-administration and interview. Agreement was assessed by nonparametric intraclass correlation coefficients.

RESULTS

A significant effect of the mode of administration was found only for past-year leisure physical activity with lower values reported in self-administered conditions compared with interview. However, a high level of concordance between the two modes of administration was observed for all variables as shown by the intraclass correlation coefficients: 0.90 for leisure physical activity (h x wk(-1)), 0.82 for occupational activity (h x wk(-1)), 0.83 for total (leisure and occupational combined) physical activity (h x wk(-1)), and 0.97 for television viewing (h x d(-1)).

CONCLUSIONS

The agreement between the two modes of administration of the questionnaire suggests that the self-administered version of the MAQ is a valuable tool to assess past-year physical activity and inactivity in self-administered conditions. This instrument could be used in large-scale population studies investigating the relationships between physical activity and health outcomes.