Objective Assessment of Physical Activity: Classifiers for Public Health.

PURPOSE: Walking for health is recommended by health agencies, partly based on epidemiological studies of self-reported behaviors. Accelerometers are now replacing survey data, but it is not clear that intensity-based cut points reflect the behaviors previously reported. New computational techniques can help classify raw accelerometer data into behaviors meaningful for public health. METHODS: Five hundred twenty days of triaxial 30-Hz accelerometer data from three studies (n = 78) were employed as training data. Study 1 included prescribed activities completed in natural settings. The other two studies included multiple days of free-living data with SenseCam-annotated ground truth. The two populations in the free-living data sets were demographically and physical different. Random forest classifiers were trained on each data set, and the classification accuracy on the training data set and that applied to the other available data sets were assessed. Accelerometer cut points were also compared with the ground truth from the three data sets. RESULTS: The random forest classified all behaviors with over 80% accuracy. Classifiers developed on the prescribed data performed with higher accuracy than the free-living data classifier, but these did not perform as well on the free-living data sets. Many of the observed behaviors occurred at different intensities compared with those identified by existing cut points. CONCLUSIONS: New machine learning classifiers developed from prescribed activities (study 1) were considerably less accurate when applied to free-living populations or to a functionally different population (studies 2 and 3). These classifiers, developed on free-living data, may have value when applied to large cohort studies with existing hip accelerometer data.

Short sleep duration is associated with higher energy intake and expenditure among African-American and non-Hispanic white adults.

Habitual short sleep duration appears to increase the risk of obesity. The objective of this paper is to investigate the association of habitual sleep duration with objective measures of energy balance. One hundred twelve African-American and 111 non-Hispanic whites aged 21-69 y participated in a cross-sectional study of dietary assessment and biomarkers. Participants reported the mean number of hours per day spent sleeping over the past year. Short sleep duration was defined as ≤6 h/d of sleep. Energy intake (kilocalories) was objectively assessed using the 2-point doubly labeled water technique to determine total energy expenditure, which is approximately equal to energy intake. Physical activity energy expenditure (kilocalories) was estimated as total energy expenditure minus each participant's calculated basal metabolic rate and the thermogenic effect of food. Compared with participants who slept ≤6 h, individuals who slept 8 h were significantly less likely to be obese (OR: 0.33; 95% CI: 0.14, 0.79). However, this association was not linear across 6-9 h of sleep (P-trend = 0.16). There was an inverse association between sleep and energy intake (P-trend = 0.07): compared with ≤6 h/d, adults who reported ≥9 h sleep consumed 178 fewer kcal/d. There was also an inverse association between sleep and physical activity (P-trend = 0.05): compared with ≤6 h/d of sleep, adults who reported 9 h of usual sleep expended 113 fewer kcal/d in physical activity. These data indicate that, compared with longer sleep duration, adults who report habitual short sleep duration have somewhat higher physical activity energy expenditure but considerably higher energy intake. Habitual short sleep duration appears to be 1 of the facets of modern life leading to a mismatch between energy intake and physical activity.

Web-based self-monitoring for weight loss among overweight/obese women at increased risk for breast cancer: the HELP pilot study.

OBJECTIVE: Excess weight and physical inactivity are modifiable risk factors for breast cancer. Training women to use self-help resources over the internet has potential for reducing intervention costs and enhancing maintenance. METHODS: A total of 50 overweight/obese women at increased breast cancer risk were randomized to a 12-week intervention or a comparison group. Telephone-based sessions trained participants to use web-based self-monitoring tools to set goals and track diet and exercise. The comparison group received dietary information but no training. At baseline and 12 weeks, participants were weighed and wore an accelerometer. RESULTS: Participants were aged 60.9 ± 0.8 years with a BMI of 33.1 ± 0.6 kg/m(2). The intervention group lost 3.3 ± 4.0 kg, whereas the comparison group gained 0.9 ± 3.4 kg (p < 0.0001). Intervention participants who found the website helpful lost 5.6 ± 0.7 kg; those who did not lost 0.8 ± 0.9 kg (p < 0.001). Change in physical activity was +70 ± 140 min/week among those who found the website helpful, -6 ± 75 min/week among those who did not, and -34 ± 207 min/week in the comparison group (p < 0.01). CONCLUSIONS: A program to train women to use web-based weight loss tools achieved a substantial short-term weight loss among the majority of participants. Further follow-up is needed to assess weight loss maintenance over time.

Classification of CAM use and its correlates in patients with early-stage breast cancer.

HYPOTHESIS: Self-reported use of complementary and alternative medicine (CAM) has been shown to increase following a cancer diagnosis, and breast cancer survivors are the heaviest users among cancer survivors. The aim of this study was to determine whether the prevalence estimate of CAM use varied according to classification of CAM. The authors used a comprehensive system to classify CAM users and test differences in demographic, lifestyle, quality of life, and cancer characteristics among them. STUDY DESIGN AND METHODS: Participants were 2562 breast cancer survivors participating in the Women's Healthy Eating and Living (WHEL) Study, aged 28 to 74 years. A structured telephone interview assessed CAM use, questioning about specific CAM practices, and whether use was related to cancer. This study examined CAM use in relation to demographics, health behaviors, and quality of life. RESULTS: Approximately 80% of the women used CAM for general purposes but only 50% reported CAM use for cancer purposes. Visual imagery, spiritual healing, and meditation were the most frequently used practices for cancer purposes. CAM use, defined as consulting a CAM practitioner and regular use, was significantly related to younger age, higher education, increased fruit and vegetable intake, and lower body mass index (P < .05). CAM users who had seen a practitioner were also more likely to report poor physical and mental health than non-CAM users (P < .05). CAM use was not associated with changes in physical and mental health between study baseline and 1-year follow-up. CONCLUSION: This study addressed important differences in the classification of CAM use among breast cancer survivors. Future studies need to further test the potential benefits and risks associated with CAM use.

Assessment of a one-page questionnaire on long-term recreational physical activity.

BACKGROUND: Physical activity is associated with a reduced risk of several chronic diseases. Although there is considerable published research on methods to assess current or recent recreational physical activity, there are few short, self-administered questionnaires designed to assess long-term physical activity. METHODS: We developed a one-page questionnaire to capture data on usual recreational physical activity during the preceding 10 years. This questionnaire was used in a cohort study of adults age 50 to 75 years residing in western Washington state. To examine the measurement characteristics of this questionnaire, we compared metabolic equivalent task (MET)-hours derived from this short questionnaire to MET-hours estimated from a detailed comparison interview in a subsample (n = 217) and to current body mass index (BMI; weight in kilograms/height in square meters) in the full sample of 57,811 persons. RESULTS: The age- and sex-adjusted partial Pearson correlation coefficient for total recreational activity between the 2 instruments was 0.68. In the full cohort, BMI was inversely correlated with physical activity as assessed by the one-page questionnaire (r = -0.22). CONCLUSIONS: This short questionnaire measures long-term physical activity at a level of precision appropriate to the examination of associations in studies of physical activity and disease.

Demographic and health-related correlates of herbal and specialty supplement use.

BACKGROUND: By broadening the definition of a dietary supplement, the 1994 Dietary Supplements Health and Education Act opened the market to many herbals, botanicals, and other food ingredients that would have otherwise needed safety testing before being sold. Information regarding patterns and correlates of herbal and specialty supplement use can help nutritionists understand which compounds are most commonly used, who are likely to use these supplements, and whether the choice of herbal supplements appears motivated by specific health concerns. METHODS: Data are from 61,587 participants, aged 50 to 76 years, who completed a self-administered mailed questionnaire in 2000-2002 on current dietary supplement use (20 herbal/specialty supplements, multivitamins, and 17 individual vitamins or minerals), demographic and lifestyle characteristics, and medical history. RESULTS: When compared with no supplement use, herbal/specialty supplement use was significantly higher among respondents who were older, female, educated, had a normal body mass index, were nonsmokers, engaged in exercise, and ate a diet lower in fat and higher in fruits and vegetables (all P<.001). Similar trends were observed when herbal/specialty supplement users were compared with vitamin/mineral users. For specific supplements and medical conditions, the strongest associations were cranberry pills and multiple bladder infections (odds ratio [OR], 4.66; 95% confidence interval [CI], 4.03-5.38), acidophilus pills and lactose intolerance (OR, 3.37; 95% CI, 2.96-3.84), and saw palmetto and enlarged prostate (OR, 3.33; 95% CI, 3.00-3.72). CONCLUSIONS: Odds of supplement use are high for certain demographic and lifestyle characteristics. Additionally, persons with specific medical conditions are using supplements promoted to reduce risk for their particular conditions.

Antioxidant supplement use in Women's Health Initiative participants.

BACKGROUND: Although antioxidant supplements are widely available and commonly used in the United States, there is a lack of detailed information on their use, including types of supplements used, doses, duration of use, and changes in use over time. METHODS: Antioxidant supplement use was assessed in participants in the Clinical Trial (n = 68,133) and Observational Study (n = 93,676) of the Women's Health Initiative. In-person interviews and a computerized inventory procedure were used to collect data on supplement use during baseline clinic visits from 1993 through 1998. RESULTS: Antioxidant supplements were widely consumed. For example, 55.5% of participants reported taking supplemental vitamin C in some form. Supplement use was positively associated with age, education, and physical activity. Most antioxidants were consumed through multivitamins. However, high doses were commonly consumed from single supplements, with 43.9% using single vitamin C supplements taking >500 mg and 86.1% using single vitamin E supplements taking >200 IU daily. Except for beta-carotene, there were increases in the use of all supplements from 1993 to 1998. CONCLUSIONS: This report demonstrates the feasibility of collecting comprehensive dietary supplement use data in large studies. These data may aid in the design of supplement use questionnaires, which could help to prevent misclassification error in epidemiologic studies of diet and disease.

Buccal cell DNA yield, quality, and collection costs: comparison of methods for large-scale studies.

There is considerable interest in noninvasive and cost-effective methods for obtaining DNA in large-scale studies. In this randomized crossover study of 22 participants, we compared the DNA yield, quality, and associated costs of buccal cell DNA collected using cytobrushes (three brushes per collection) and swish (i.e., mouthwash) in self-administered procedures. There was a nonstatistically significant higher yield from the mouthwash compared with cytobrush collections (15.8 microg versus 12.0 microg, respectively; P = 0.53). PCR reactions that required short (0.3 kb) or intermediate (1.1 kb) DNA fragments were 100% successful for DNA from brush and mouthwash, whereas PCRs for reactions that required long fragments (7.8 kb) failed for all of the participants from cytobrush DNA and were 81% successful for DNA from the mouthwash source. The brush collections provided sufficient DNA for an estimated 150-225 PCR reactions requiring short and intermediate DNA fragments. The estimated per person costs for buccal brush DNA collections in large studies were less then half (8.50 dollars) those for the mouthwash method (18 dollars). In addition, we tested whether cytobrush instructions to rub cheeks before collection or collect cells only in the morning increased DNA yield and whether repeat brushings of the same cheek reduced DNA yield. These variations resulted in no significant differences in DNA yields. We conclude that the collection of DNA with cytobrushes using simple instructions is cost effective in large-scale studies, and yields sufficient quantity and quality of DNA for genotyping.

Types of alternative medicine used by patients with breast, colon, or prostate cancer: predictors, motives, and costs.

OBJECTIVE: Assess predictors and costs of various types of alternative medicine used by adult patients with cancer. DESIGN, LOCATION, SUBJECTS: Telephone survey of 356 patients with colon, breast, or prostate cancer identified from the population-based Cancer Surveillance System of western Washington. RESULTS: Overall, 70.2% of patients used at least one type of alternative medicine, with 16.6% seeing alternative providers, 19.1% using mental/other therapy, and 64.6% taking dietary supplements. Compared to males, females were five times more likely to see an alternative provider and about twice as likely to use mental therapies or supplements (p < 0.05 for all). Older patients were less likely to use mental/other therapy. Higher education (but not income) was associated with use of all types of alternative medicine. Patients with multiple medical treatments were two times more likely to take dietary supplements compared to patients having only surgery (p < 0.01). Varying by the type of alternative therapy, 83%-97% of patients reported that they used alternative medicine for general health and well-being while 8% to 56% reported use for treatment of cancer. Almost all patients reported that the alternative therapy improved their well-being. Expenditures for alternative medicine averaged $68 per user per year, but ranged from $4 to $14,659. CONCLUSIONS: Given the high prevalence of use and that patients believed that alternative medicine improved their well-being, clinicians should show an open mind toward these treatment choices and encourage frank discussion. Familiarity and some knowledge regarding use of alternative medicine is important in cases where interactions between conventional and alternative medicine may occur. It is also important to identify potential patient needs for mental health support beyond conventional care and support patients who want to make healthful lifestyle changes. Longitudinal investigations are urgently needed to investigate associations of alternative medicine use with survival and quality of life in patients with cancer.

Psychosocial predictors of diet and acculturation in Chinese American and Chinese Canadian women.

OBJECTIVE: To examine the influence of diet-related psychosocial constructs on the dietary practices of Chinese populations living in North America. DESIGN: Data are from a cross-sectional survey of 244 women of Chinese ethnicity living in Seattle, WA, USA and Vancouver, BC, Canada. Using an interviewer-administered questionnaire and PRECEDE/PROCEED as our model, we collected information on diet-related psychosocial (predisposing, enabling, and reinforcing) factors; consumption of foods reflecting Western and Chinese dietary practices; and past and current consumption of fruits, vegetables and fat. RESULTS: Participants generally believed that there were strong relationships between diet and health, but only about a quarter were aware of nutrition information from the government. Food cost, availability, and convenience did not appear to be major concerns among these participants. Respondents' older relatives and spouses tended to prefer a Chinese diet and also had a strong influence on the household diet. Associations of the psychosocial factors with demographic characteristics, adoption of Western dietary practices, and consumption of fruits and vegetables were informative. For example, older, less educated respondents considered it very important to eat a low fat, high fruit and vegetable diet; while younger, more educated participants who were employed outside the home did not think the Chinese diet is healthier than a typical Western diet (all p < 0.05). Western acculturated respondents were more likely to believe in a relationship between diet and cancer/heart disease and report that preparing Chinese meals is inconvenient (p < 0.05). Respondents with in-family normative pressure to maintain Chinese eating patterns ate more fruits and vegetables (4.4 vs 3.7 servings), while knowledge of nutrition information from the government was associated with increased fruit and vegetable consumption after immigration (all p < 0.05). CONCLUSIONS: Chinese cultural beliefs play an important role in the dietary practices of Chinese living in North America. Therefore, traditional health beliefs, as well as socioeconomic and environmental factors related to diet should be incorporated into the design and implementation of culturally appropriate health promotion programs for Chinese immigrants.