Physical activity and sedentary behavior patterns using accelerometry from a national sample of United States adults.

BACKGROUND: This study described the patterns of accelerometer-determined physical activity and sedentary behavior among adults using a nationally representative sample from the United States. METHODS: Using 2003-2006 National Health and Nutrition Examination Survey (NHANES) data, 7931 adults at least 18 years old wore an ActiGraph accelerometer for one week, providing at least 3 days of wear for >=8 hours/day. Cutpoints defined moderate to vigorous physical activity (MVPA; >= 2020 and >=760 counts/minute), vigorous physical activity (> = 5999 counts/minute), and sedentary behavior (<100 counts/minute). Latent class analysis (LCA) was used to estimate patterns of physical activity and sedentary behavior. All estimates were weighted to reflect the United States population. RESULTS: For weighted percent of MVPA out of total wearing time, 5 classes were identified from least to most active: 65.3% of population (weighted mean 9.3 minutes/day), 24.9% (32.1 minutes/day), 3.2% that was low on the weekdays but much higher on the weekends (52.0 minutes/day), 5.9% (59.9 minutes/day), and 0.7% in the highest class (113.6 minutes/day). Using the lower MVPA threshold, 6 classes emerged with each class ranging in population from 1.2% to 43.6%. A vigorous activity class could not be derived due to low prevalence. For weighted percent of sedentary behavior out of total wearing time, 5 classes were identified from most to least sedentary: 6.3% of population (weighted mean 660.2 minutes/day), 25.1% (546.8 minutes/day), 37.7% (453.9 minutes/day), 24.0% (354.8 minutes/day), and 7.0% (256.3 minutes/day). Four of the classes showed generally similar results across every day of the week, with the absolute percents differing across classes. In contrast, the least sedentary class showing a marked rise in percent of time spent in sedentary behavior on the weekend (weighted mean 336.7-346.5 minutes/day) compared to weekdays (weighted mean 255.2-292.4 minutes/day). CONCLUSION: The LCA models provided a data reduction process to identify patterns using minute-by-minute accelerometry data in order to explore meaningful contrasts. The models supported 5 or 6 distinct patterns for MVPA and sedentary behavior. These physical activity and sedentary behavior patterns can be used as intervention targets and as independent or dependent variables in future studies of correlates, determinants, or outcomes.

Cardiometabolic correlates of low type 2 diabetes incidence in western Alaska Native people - The WATCH study.

AIMS: Previously rare among Alaska Native (AN) people, type 2 diabetes (DM2) prevalence as indicated by registry data has increased by as much as 300% in some western Alaska regions. We sought to determine prevalence and incidence of DM2 and analyze associated cardiometabolic risk factors in western AN people. METHODS: DM2 and prediabetes prevalence and incidence were determined by the Western Alaska Tribal Collaborative for Health using consolidated data from cohort studies conducted during 2000-2010. Crude and age-adjusted incidence for DM2 and prediabetes were calculated using 2010 American Diabetes Association criteria. Effects of covariates on DM2 and prediabetes were determined using univariate and multivariate Cox proportional hazards analyses, adjusted for age and sex. RESULTS: Excluding baseline diabetes (n=124, 4.5%), 53 cases of new DM2 were identified among 2630 participants. Age- and sex-adjusted DM2 incidence was 4.3/1000 (95% CI 2.9, 5.0) person-years over an average 5.9-year follow up. After excluding baseline prediabetes, 387 new cases of prediabetes were identified among 1841 participants; adjusted prediabetes incidence was 44.5/1000 (95% CI 39.5, 49.5) person years. Independent predictors for DM2 included age, impaired fasting glucose, and metabolic syndrome; family history of diabetes and obesity were additional independent predictors for prediabetes. CONCLUSIONS: DM2 incidence in western AN people is substantially lower than that for U.S. whites; however, incidence of prediabetes is more than 10-fold higher than western AN DM2 incidence and more closely aligned with U.S. rates. Interventions aimed at achieving healthy lifestyles are needed to minimize risk factors and maximize protective factors for DM2 in this population.

Prevalence of Hypertension and Associated Risk Factors in Western Alaska Native People: The Western Alaska Tribal Collaborative for Health (WATCH) Study.

Hypertension is a common chronic disease and a key risk factor in the development of cardiovascular disease. The Western Alaska Tribal Collaborative for Health study consolidates baseline data from four major cohorts residing in the Norton Sound and Yukon-Kuskokwim regions of western Alaska. This consolidated cohort affords an opportunity for a systematic analysis of high blood pressure and its correlates in a unique population with high stroke rates over a wide age range. While the prevalence of hypertension among western Alaska Native people (30%, age-standardized) is slightly less than that of the US general population (33%), cardiovascular disease is a leading cause of mortality in this rural population. The authors found that improvement is needed in hypertension awareness as about two thirds (64%) of patients reported awareness and only 39% with hypertension were controlled on medication. Future analyses assessing risk and protective factors for incident hypertension in this population are indicated.

College students' knowledge about fetal alcohol spectrum disorder.

BACKGROUND: Fetal Alcohol Spectrum Disorders (FASDs) are the leading known preventable birth defects in North America. Knowledge surveys about FASD have been conducted with various health and allied healthcare providers and have proven useful in identifying gaps in knowledge and differences among provider groups to support prevention efforts. To date, no research has been conducted exploring FASD knowledge among college students. OBJECTIVE: This study explored FASD knowledge in a sample of college students, a group at particularly high risk for alcohol-exposed pregnancies. Findings are compared to professionals in several healthcare and affiliated professional groups who were previously surveyed with the same FASD-related items. METHODS: Surveys from 1,035 college students at a northwestern university were analyzed. Included with the ACHA-National College Health Assessment II were questions regarding FASD. College students' knowledge was compared with that of professionals in key healthcare and affiliated positions to define their relative awareness of FASD risk. RESULTS: Overall, findings revealed adequate FASD knowledge among college students. Although minor differences emerged when comparing students and professionals' responses, most respondent groups answered with an 85% accuracy rate or higher. CONCLUSION: College students demonstrated adequate knowledgeable about FASD. Future research must explore whether such knowledge translates into lower risk behavior and consequent reduction in alcohol-exposed pregnancies.

All-cause, cardiovascular, and cancer mortality in western Alaska Native people: western Alaska Tribal Collaborative for Health (WATCH).

OBJECTIVES: We determined all-cause, cardiovascular disease (CVD), and cancer mortality in western Alaska Native people and examined agreement between death certificate information and adjudicated cause of deaths. METHODS: Data from 4 cohort studies were consolidated. Death certificates and medical records were reviewed and adjudicated according to standard criteria. We compared adjudicated CVD and cancer deaths with death certificates by calculating sensitivity, specificity, predictive values, and κ statistics. RESULTS: Men (n = 2116) and women (n = 2453), aged 18 to 95 years, were followed an average of 6.7 years. The major cause of death in men was trauma (25%), followed by CVD (19%) and cancer (13%). The major cause of death in women was CVD (24%), followed by cancer (19%) and trauma (8%). Stroke rates in both genders were higher than those of US Whites. Only 56% of deaths classified as CVD by death certificate were classified as CVD by standard criteria; discordance was higher among men (55%) than women (32%; κs = 0.4 and 0.7). CONCLUSIONS: We found lower rates for coronary heart disease death but high rates of stroke mortality. Death certificates overestimated CVD mortality; concordance between the 2 methods is better for cancer mortality. The results point to the importance of cohort studies in this population in providing data to assist in health care planning.

Agreement Between Self-Report and Medical Record Prevalence of 16 Chronic Conditions in the Alaska EARTH Study.

The gold standard for health information is the health record. Hospitalization and outpatient diagnoses provide health systems with data on which to project health costs and plan programmatic changes. Although health record information may be reliable and perceived as accurate, it may not include population-specific information and may exclude care provided outside a specific health care facility. Sole reliance on medical record information may lead to underutilization of health care services and inadequate assessment of population health status. In this study, we analyzed agreement, without assuming a gold standard, between self-reported and recorded chronic conditions in an American Indian/Alaska Native cohort. Self-reported health history was collected from 3821 adult participants of the Alaska EARTH study during 2004-2006. Participant medical records were electronically accessed and reviewed. Self-reported chronic conditions were underreported in relation to the medical record and both information sources reported the absence more reliably than the presence of conditions (across conditions, median positive predictive value = 64%, median negative predictive value = 94%). Agreement was affected by age, gender, and education. Differences between participant- and provider-based prevalence of chronic conditions demonstrate why health care administrators and policy makers should not rely exclusively on medical record-based administrative data for a comprehensive evaluation of population health.

Utilizing harmonization and common surveillance methods to consolidate 4 cohorts: the Western Alaska Tribal Collaborative for Health (WATCH) study.

BACKGROUND: According to health status reports, chronic disease prevalence appears to be rising in western Alaska Native (AN) people, and accurate population-based data are needed. Four cohort studies of western AN people were conducted in the Norton Sound and Yukon-Kuskokwim regions, but none have been large enough to allow reliable estimates of rates of chronic diseases and evaluate their risk factors. OBJECTIVE: In this article, the methods used to combine 4 major cohort studies of rural western AN people are described and the benefits and challenges encountered in combining data and standardizing surveillance methods for these studies are discussed. DESIGN: Tribal permission was obtained for each cohort study and the consolidated study. Data from baseline exams were directly combined or harmonized into new variables. Common surveillance methods were developed and implemented to identify incidence and risk factors for cardiovascular disease (CVD) events and type 2 diabetes. RESULTS: A cohort of 4,569 western AN participants (2,116 men and 2,453 women), aged 18-95 years, was established to study CVD and diabetes prevalence. Prospective surveillance data over an average 6.7-year follow-up can now be used to study CVD and diabetes incidence and associated risk factors in a subset of 2,754 western AN participants (1,218 men and 1,536 women) who consented to initial surveillance. CONCLUSIONS: The combined cohort provides statistical power to examine incidence rates and risk factors for CVD and diabetes and allows for analyses by geographic region. The data can be used to develop intervention programmes in these populations and others.

Associations between patterns of objectively measured physical activity and risk factors for the metabolic syndrome.

PURPOSE: To determine whether certain patterns of objectively measured physical activity (PA) are associated with the risk factors for or the diagnosis of the metabolic syndrome (MS). DESIGN: Latent class analysis, including assessment of the associations between latent PA classes and risk factors for the MS. SETTING: Random sample from throughout the United States using data from the 2003-2004 National Health and Nutrition Examination Survey. SUBJECTS: A total of 3458 civilian adult noninstitutionalized U.S. citizens. MEASURES: Daily minutes of moderate-to-vigorous PA across a 7-day week based on accelerometer measurements, as well as high blood pressure, blood glucose levels, triglyceride levels, and body mass index, along with low levels of high density lipoproteins, using clinical cut points. RESULTS: Membership in the more active PA classes was consistently associated with lower odds of all risk factors for the MS. However, when participants were categorized into quartiles of the coefficients of variation of PA across 7 days, few differences were seen in any of the risk factors. CONCLUSIONS: Accumulating the total weekly recommended amount of PA is consistently associated with positive health profiles, and more PA than the recommended amounts may be even better. However, the manner in which this activity is accumulated, either spread over most days of the week or compressed into just a couple of days, may have similar associations with the risk factors for the MS.

Patterns of objectively measured physical activity in the United States.

PURPOSE: We used latent class analysis (LCA) to assess patterns of physical activity among adults, using the 7 d of accelerometer data from the 2003-2004 NHANES. METHODS: For each participant, we determined the daily minutes of moderate-to-vigorous physical activity (MVPA), vigorous physical activity (VPA), and minutes of MVPA that occurred in bouts of 10 min. Participants were then categorized into patterns of activity, using LCA and adjusting for sociodemographic characteristics. RESULTS: For overall MVPA, five classes of physical activity were defined, including two least active classes, which averaged less than 25 min of MVPA per day and represented 78.7% of the total study population. The most active class averaged 134 min of MVPA per day and comprised 0.9% of the population. The results for bout minutes of MVPA were similar to the patterns produced for overall MVPA, with the exception of a "weekend warrior" class with moderate levels of physical activity Monday through Friday but with a much higher level of activity on the weekend, particularly on Sunday. This class represented 1.8% of the population. Only 1.4% of all days achieved 10 min or more of VPA, and in 91.1% of all days, participants accumulated less than 1 min of VPA. The LCA analysis of VPA did not produce stable results, because of the small number of participants registering any minutes of VPA. CONCLUSION: Our results indicate that a very large portion of the U.S. population may be classified into patterns of physical activity that represent low levels of MVPA throughout the week. The LCA analysis provided a novel approach for assessing patterns of objectively measured physical activity in epidemiologic studies.

Motor vehicle mismatch-related spinal injury.

BACKGROUND/OBJECTIVE: Motor vehicle collision (MVC)-related spinal cord injury (SCI) is the most prevalent etiology of SCI. Few studies have defined SCI risk factors. Vehicle mismatch occurs in 2-vehicle MVCs in which there are significant differences in vehicle weight, stiffness, and height. This study examined SCI risk and vehicle mismatch. METHODS: A matched case-control study using the 1995 to 2003 National Automotive Sampling System (NASS). Study subjects were identified from 2-vehicle MVCs. Cases were occupants who had suffered a cervical, thoracic, or lumbar SCI. Odds ratios (ORs) and 95% confidence intervals (CIs) were calculated. RESULTS: There were 101,682 cases of SCI matched to 805,091 controls. Occupants of passenger vehicles involved in MVCs with a light truck or van (LTV) were at increased risk for SCI (OR = 1.87, 95% CI = 1.07-3.24) and this risk was greatest for thoracic SCI (OR = 5.09, 95% CI = 2.33-11.13). In addition, occupants of LTVs involved in MVCs with passenger vehicles were at significant increased risk for cervical (OR = 1.39) and lumbar (OR = 2.65) SCI; and occupants of LTVs involved in MVCs with other LTVs were at increased risk of any SCI (OR = 2.02, 95% CI = 1.52-2.69). For these subjects, significant increased risks were seen for all spine regions: cervical (OR = 1.41), thoracic (OR = 2.86), and lumbar (OR = 2.38). CONCLUSIONS: The results of this study suggest that occupants of passenger vehicles are at increased SCI risk when involved in 2-vehicle MVCs with LTVs; and that occupants of LTVs are at increased SCI risk, regardless.

Relationship between age and lower extremity fractures in frontal motor vehicle collisions.

BACKGROUND: Older adults (aged > or = 65 years) represent the single fastest growing segment of the United States population and will comprise one in five Americans during the third decade of this century. As this population segment rapidly expands, lower extremity fractures (LE Fx) and their associated disability will become a greater public health concern. The purpose of this study was to quantify the risk for LE Fx from motor vehicle collisions (MVCs) according to age. METHODS: The 1995 to 2000 National Automotive Sampling System data files were used. Study entry was limited to front-seat occupants involved in frontal MVCs. Risk ratios for LE Fx and age were adjusted for gender, driver versus passenger, seat belt use, airbag deployment, delta-V, intrusion, and vehicle type. RESULTS: Beginning in the fourth decade, there was a trend of higher relative risk for LE Fx with age that reached statistical significance in the seventh decade of life. CONCLUSION: This study documented an increased risk of LE Fx in older MVC occupants. Efforts to prevent these disabling injuries and to better protect occupants' lower extremities in MVCs should include improved vehicle design and reevaluation of the existing federal motor vehicle safety standards.

Injury rates among restrained drivers in motor vehicle collisions: the role of body habitus.

BACKGROUND: Previous studies have examined the independent effects of occupant height, obesity, and body mass index in motor vehicle collisions and identified related injury patterns. The hypothesis of this study was that as the driver's body habitus diverges from the 50% percentile male Hybrid III Crash Dummy (H3CD), the frequency of injury changes. METHODS: The 1995 to 1999 National Automotive Sampling System Crashworthiness Data System was used. Study entry was limited to restrained drivers who were then subdivided into height and weight categories. Incidence rates were calculated for injuries to selected body regions as defined by the Abbreviated Injury Scale for overall, frontal, and driver's side collisions. RESULTS: When grouped according to height and weight as descriptors of body habitus, injury rates for restrained drivers were increased as well as decreased in several subgroups. This association was seen in overall, frontal, and driver's side collisions. CONCLUSION: The H3CD plays a major role in vehicular cabin interior design and crash testing. For drivers with a body habitus different from that of the H3CD, the vehicle cabin/body fit changes and the safety features may perform differently, which could account for these observations.