Biomedical subjects

J R Hebert

Publications and source records attributed to J R Hebert.

At least 19 recordsLinked to original sources

PubMed2006

Seasonal variation in food intake, physical activity, and body weight in a predominantly overweight population.

OBJECTIVE: To describe seasonal variation in food intake, physical activity, and body weight in a predominantly overweight population. DESIGN: A longitudinal observational study. SETTING: Most of the study participants were recruited from a health maintenance organization (HMO) in central Massachusetts, USA. Additional individuals of Hispanic descent were recruited from outside of the HMO population to increase the ethnic diversity of this sample. SUBJECTS: Data from 593 participants, aged 20-70, were used for this investigation. Each participant was followed quarterly (five sampling points: baseline and four consecutive quarters) for 1-year period. Body weight measurements and three 24-h dietary and physical activity recalls were obtained on randomly selected days (including 2 weekdays and 1 weekend day) per quarter. Sinusoidal regression models were used to estimate peak-to-trough amplitude and phase of the peaks. RESULTS: Daily caloric intake was higher by 86 kcal/day during the fall compared to the spring. Percentage of calories from carbohydrate, fat and saturated fat showed slight seasonal variation, with a peak in the spring for carbohydrate and in the fall for total fat and saturated fat intake. The lowest physical activity level was observed in the winter and the highest in the spring. Body weight varied by about 1/2 kg throughout the year, with a peak in the winter (P<0.001 winter versus summer). Greater seasonal variation was observed in subjects who were male, middle aged, nonwhite, and less educated. CONCLUSIONS: Although there is seasonal variation in diet, physical activity and body weight, the magnitude of the change is generally small in this population. SPONSORSHIP: US National Heart, Lung and Blood Institute.

Adult↗

PubMed2004

Variation in nutrient intakes among women in Shanghai, China.

BACKGROUND: In 1997, we launched a large population-based cohort study, the Shanghai Women Health Study (SWHS), to investigate diet in relation to cancer risk among 74 943 Chinese women. Simultaneously, a dietary calibration study was conducted among 200 SWHS participants with biweekly 24-h dietary recall (24HDR) over a 1-y period in order to evaluate the validity and reliability of the SWHS food frequency questionnaire (FFQ). OBJECTIVE: The objectives of the current study were to evaluate the nature and magnitude of variances for intake of 26 nutrients among SWHS participants, and to estimate the number of 24HDR needed for estimate intake of the 26 nutrients examined in the study population. DESIGN: In all, 1-y biweekly 24HDR collected from 200 healthy, free-living women aged between 40 and 70 y, who participated in the SWHS dietary calibration study, was analyzed by mixed effects model and ratios of within-individual and between-individual dietary intake variances (sigma(w)(2)/sigma(b)(2)) were estimated. RESULTS: In agreement with reports from studies conducted in the US, we found that within-individual variances were larger than between-individual variances in dietary intake of most nutrients. The sum of all other variation (eg, weekday and weekend, seasonal, interviewer) accounted for less than 5% of total variation. Ratios of within- to between-individual variances (for log transformed data) ranged from 1.05 (carbohydrate) to 2.79 (fat) for macronutrient intake, 1.74 (niacin) to 8.48 (delta-tocopherol) for vitamin intake, and 1.35 (phosphorus) to 5.59 (sodium) for mineral intake. CONCLUSIONS: The results of this study suggest that within- and between-individual differences in nutrient intake are the major sources of variation in this population of adult Chinese women. Cultural practices as well as seasonal supply and consumption patterns of vegetable intake are likely the major contributors to the variation. Implications of these results are discussed.

Adult↗

PubMed2002

Design of an intervention addressing multiple levels of influence on dietary and activity patterns of low-income, postpartum women.

Low-income, multi-ethnic women are at elevated risk for obesity and chronic diseases, yet influences at different levels may act as barriers to changing risk behaviors. Following the birth of a child, childrearing and social isolation can exacerbate these influences. The social ecological framework integrates behavior-change strategies at different levels, providing a strong theoretical base for developing interventions in this high-risk population. The primary purpose of this randomized controlled trial is to test the efficacy of an educational model delivered by community-based paraprofessionals in improving diet, activity and weight loss among new mothers over a 12-month postpartum period and a 6-month maintenance period. This model fosters institutional change to support behavior changes influenced at intrapersonal and interpersonal levels, through collaboration with federal programs for low-income families: the Special Supplemental Food Program for Women, Infants and Children (WIC), and the Expanded Food and Nutrition Education Program (EFNEP). Participants are randomized to the Usual Care, e.g. WIC nutrition and breastfeeding education, or Enhanced EFNEP intervention arm, consisting of Usual WIC Care plus a sustained, multi-component intervention including home visits, group classes and monthly telephone counseling. If shown to be efficacious, this program will be readily sustainable through existing federal agencies.

Adult↗

PubMed2002

Descriptive epidemiology of body mass index of an urban adult population in western India.

STUDY OBJECTIVE: To describe height, weight, and body mass index (BMI) of the adult urban population in Mumbai, western India and to estimate the prevalence and severity of thinness and overweight in this population. To describe the association of BMI with education, age, and tobacco habits in an urban Indian population. DESIGN: Cross sectional representative survey of 99 598 adults (40 071 men and 59 527 women). SETTING: The survey was carried out in the city of Mumbai (formerly known as Bombay) in western India. PARTICIPANTS: Men and women aged > or =35 years who were residents of the main city of Mumbai. MAIN RESULTS: The mean height, weight, and BMI were 161.0 (SD 6.7) cm, 56.7 (SD 11.0) kg, and 21.8 (SD 3.8) kg/m(2) for men and 148.0 (SD 6.2) cm, 49.8 (SD 11.2) kg, and 22.7 (SD 4.7) kg/m(2) for women, respectively. Some 19% of men and women were thin (BMI<18.5 kg/m(2)), while 19% of men and 30% of women were overweight (BMI> or =25kg/m(2)). Multivariable logistic regression analyses showed that age, level of education, and tobacco use were independently associated with BMI. The odds ratio (OR) and 95% confidence intervals (CI) for thinness (BMI<18.5 kg/m(2)) were OR 6.52, 95%CI 5.38 to 7.89 for men and OR 4.83, 95%CI 3.71 to 6.28 for women, respectively, (p<0.001) for the lowest level of education (illiterate group). The OR and 95%CI for overweight were 2.25, 2.20 to 2.58 for college educated men and 1.90, 1.64 to 2.20 for college educated women, respectively, p<0.001. Both smoking (2.33, 2.09 to 2.59; 2.89, 1.77 to 4.72 for men and women, respectively, p<0.001) and smokeless tobacco use (1.65, 1.52 to 1.80; 2.26, 2.14 to 2.38 for men and women, respectively p<0.0001) were significantly associated with low BMI. CONCLUSIONS: Sequelae of thinness and overweight represent major public health problems. The results of this study, indicating an equal prevalence of thinness and overweight in an urban area and their association with age, level of education, and tobacco use raise concerns of an emerging public health crisis in urban India.

Adult↗

PubMed2001

Association of body size and fat distribution with risk of breast cancer among Chinese women.

Most previous studies addressing the association of body size, weight change and body fat distribution with the risk of breast cancer were conducted in Western societies with a high proportion of overweight people. It remains unclear whether the dose-response relation observed in earlier studies can be extended to women with "normal" weight based on prevailing Western standards. To address this issue, we analyzed data from a population-based case-control study of breast cancer recently completed among Chinese women in urban Shanghai. In-person interviews and anthropometric measurements were completed for 1,459 women newly diagnosed with breast cancer from 25 to 64 years of age and 1,556 controls frequency-matched to cases on age. Unconditional logistic regression was employed to estimate adjusted odds ratios (ORs) and 95% confidence intervals (CI) related to anthropometric variables and self-reported body weight. Currently measured weight, body mass index [BMI: weight (kg)/height(m)(2)] or height was each found to be positively related to risk of postmenopausal breast cancer in a dose-response manner, with ORs (95% CI) being 2.0 (1.4-3.0), 2.0 (1.2-3.2) or 1.7 (1.2-2.5), respectively, for the highest category of weight, BMI or height compared to the lowest category of these variables. These variables were unrelated to premenopausal breast cancer risk. Reported weight at ages >40 years and weight gain after age 20 were more predictive for postmenopausal breast cancer than weight at an earlier age. After adjustment for BMI, waist-to-hip ratio was related to an increased risk of premenopausal [OR = 1.7 (1.3-2.3) for the highest category compared to the lowest category] but not postmenopausal breast cancer. This study suggests that, even in a relatively thin Chinese population, weight gain and height are related to an increased risk of postmenopausal breast cancer, while central fat distribution was associated with premenopausal breast cancer. General weight control may be an effective measurement for breast cancer prevention.

Adipose Tissue↗

PubMed2001

Dietary folate intake and breast cancer risk: results from the Shanghai Breast Cancer Study.

Folate is involved in DNA synthesis, repair, and methylation. It has been hypothesized that high intake of folate may reduce the risk of human cancers, including cancer of the breast. Using data from a population-based case-control study of breast cancer conducted in urban Shanghai during 1996-1998, we evaluated the association of dietary folate intake and breast cancer risk among 1321 cases and 1382 controls, 25-64 years of age, who never drank alcohol regularly or used vitamin supplements. Usual dietary habits were assessed with an in-person, interviewer-administered food frequency questionnaire developed and tested for use in this population. Unconditional logistic regression models were used to calculate odds ratios (ORs) and their 95% confidence intervals (95% CIs) after adjusting for potential confounding factors. Dietary folate intake was inversely associated with breast cancer risk (P for trend, 0.05) with an adjusted OR of 0.71 (95% CI, 0.56-0.92) observed among women who were in the highest quintile of intake. The inverse association was stronger after further adjusting for total fruit and vegetable and animal food intakes (OR, 0.62; 95% CI, 0.46-0.82; P for trend, 0.01). A more pronounced inverse association between folate intake and breast cancer risk (OR, 0.47; 95% CI, 0.25-0.88; P for trend, 0.01) was observed among women who consumed high levels of folate cofactors (methionine, vitamin B(12), and vitamin B(6)) than those whose intake levels of these nutrients were low. Dietary intake of methionine, vitamin B(12), and vitamin B(6) were not independently related to risk of breast cancer after adjusting for confounding factors. Thus, our study adds additional support to the protective role of dietary folate in breast carcinogenesis and suggests further that the effect of folate may be modified by dietary intake of methionine, vitamin B(12), and vitamin B(6).

Adult↗

PubMed2001

Sources of variance in daily physical activity levels in the seasonal variation of blood cholesterol study.

The authors examined sources of variance in self-reported physical activity in a cohort of healthy adults (n = 580) from Worcester, Massachusetts (the Seasonal Variation of Blood Cholesterol Study, 1994-1998). Fifteen 24-hour physical activity recalls of total, occupational, and nonoccupational activity (metabolic equivalent-hours/day) were obtained over 12 months. Random effects models were employed to estimate variance components for subject, season, day of the week, and residual error, from which the number of days of assessment required to achieve 80% reliability was estimated. The largest proportional source of variance in total and nonoccupational activity was within-subject variance (50-60% of the total). Differences between subjects accounted for 20-30% of the overall variance in total activity, and seasonal and day-of-the-week effects accounted for 6% and 15%, respectively. For total activity, 7-10 days of assessment in men and 14-21 days of assessment in women were required to achieve 80% reliability. For nonoccupational activity, 21-28 days of assessment were required. This study is among the first to have examined the sources of variance in daily physical activity levels in a large population of adults using 24-hour physical activity recall. These findings provide insight for understanding the strengths and limitations of short term and long term physical activity assessments employed in epidemiologic studies.

Activities of Daily Living↗

PubMed2001

Lifetime physical activity and breast cancer risk in the Shanghai Breast Cancer Study.

Overall physical activity in adolescence and adulthood, and changes in activity over the lifespan were analysed by in-person interviews among 1459 women newly diagnosed with breast cancer and 1556 age-matched controls in urban Shanghai. Physical activity from exercise and sports, household, and transportation (walking and cycling) was assessed in adolescence (13-19 y) and adulthood (last 10 y), as was lifetime occupational activity. Logistic regression was used to estimate odds ratios (OR) and 95% confidence limits (OR (95% CL)) while controlling for confounders. Risk was reduced for exercise only in adolescence (OR = 0.84 (0.70-1.00)); exercise only in adulthood (OR = 0.68 (0.53-0.88)), and was further reduced for exercise in both adolescence and adulthood (OR = 0.47 (0.36-0.62)). Graded reductions in risk were noted with increasing years of exercise participation (OR(1-5 yrs)= 0.81 (0.67-0.94); OR(6-10 yrs)= 0.74 (0.59-0.93); OR(11-15 yrs)= 0.55 (0.38-0.79); OR(16 + yrs)= 0.40 (0.27-0.60);P(trend,)< 0.01). Lifetime occupational activity also was inversely related to risk (P(trend)< 0.01). These findings demonstrate that consistently high activity levels throughout life reduce breast cancer risk. Furthermore, they suggest that women may reduce their risk by increasing their activity levels in adulthood.

Adolescent↗

PubMed2001

Seasonal variation in household, occupational, and leisure time physical activity: longitudinal analyses from the seasonal variation of blood cholesterol study.

The authors examined seasonal variation in physical activity in longitudinal analyses of 580 healthy adults from Worcester, Massachusetts (the Seasonal Variation of Blood Cholesterol Study, 1994-1998). Three 24-hour physical activity recalls administered five times during 12 months of follow-up were used to estimate household, occupational, leisure time, and total physical activity levels in metabolic equivalent (MET)-hours/day. Trigonometric models were used to estimate the peak-to-trough amplitude and phase of the peaks in activity during the year. Total activity increased by 1.4 MET-hours/day (121 kcal/day) in men and 1.0 MET-hours/day (70 kcal/day) in women during the summer in comparison with winter. Moderate intensity nonoccupational activity increased by 2.0-2.4 MET-hours/day in the summer. During the summer, objectively measured mean physical activity increased by 51 minutes/day (95% confidence interval: 20, 82) in men and by 16 minutes/day (95% confidence interval: -12, 45) in women. The authors observed complex patterns of seasonal change that varied in amplitude and phase by type and intensity of activity and by subject characteristics (i.e., age, obesity, and exercise). These findings have important implications for clinical research studies examining the health effects of physical activity and for health promotion efforts designed to increase population levels of physical activity.

Adult↗

PubMed2001

Behavioral risk factors among members of a health maintenance organization.

BACKGROUND: Co-occurrence of risk behaviors (RBs) substantially increases the risk of disease. This study examines the co-occurrence of four health risk behaviors (i.e., smoking, high-fat diet, sedentariness, and high-risk drinking) and demographic and psychosocial variables associated with number of RBs in a sample of members of a health maintenance organization who participated in the Seasonal Variation in Cholesterol (Seasons) study. METHODS: Seasons study baseline data were used. Subjects completed a self-administered questionnaire packet containing questions on demographics, smoking history, and leisure-time physical activity, a 7-day dietary recall instrument, and various psychosocial measures. Results presented here are based on 496 subjects with complete data on all RBs. RESULTS: Forty-three percent of participants had > or = two RBs. The most prevalent RB combination was high-fat diet/sedentariness, with 30% of subjects reporting both RBs. Associations between RBs were observed. A greater number of RBs were observed among younger and less-educated subjects, those with higher depression scores, and subjects who perceived their health as poor. CONCLUSIONS: Findings highlight the importance of designing and evaluating primary care-based screening programs and interventions for multiple RBs.

Adult↗

PubMed2001

Facilitating dietary change: the patient-centered counseling model.

Recent data indicate that the patient-centered counseling model enhances long-term dietary adherence. This model facilitates change by assessing patient needs and subsequently tailoring the intervention to the patient's stage in the process of change, personal goals, and unique challenges. This article describes this model, including its theoretical foundations, a 4-step counseling process, and applications. This behavioral counseling model can help nutrition professionals enhance patient adherence to nutrition care plans and dietary guidelines.

Behavior Therapy↗

PubMed2001

Change in women's diet and body mass following intensive intervention for early-stage breast cancer.

OBJECTIVE: To determine the effectiveness of an intensive dietary intervention on diet and body mass in women with breast cancer. DESIGN: Randomized clinical trial. SUBJECTS: 172 women aged 20 to 65 years with stage I or II breast cancer. INTERVENTION: A 15-session, mainly group-based and dietitian-led nutrition education program (NEP) was compared to a mindfulness-based stress reduction clinic program (SRC); or usual supportive care (UC). MAIN OUTCOME MEASURES: Dietary fat, complex carbohydrates, fiber, and body mass were measured. STATISTICAL ANALYSIS: In addition to descriptive statistics, analysis of variance was conducted to test for differences according to intervention group. RESULTS: Of the 157 women with complete dietary data at baseline, 149 had complete data immediately postintervention (at 4 months) and 146 had complete data at 1 year. Women randomized to NEP (n = 50) experienced a large reduction in fat consumption (5.8% of energy as fat) at 4 months and much of this reduction was preserved at 1 year (4.1% of energy) (both P < .0002) vs no change in either SRC (n = 51) or UC (n = 56). A 1.3-kg reduction in body mass was evident at 4 months in the NEP group (P = .003) vs no change in the SRC and UC groups. Women who had higher-than-average expectations of a beneficial effect of the intervention experienced larger changes. APPLICATIONS: Dietitians' use of group nutrition interventions appear to be warranted. Increasing their effectiveness and maintaining high levels of adherence may require additional support, including the involvement of significant others, periodic individual meetings, or group booster sessions.

Adult↗

PubMed2001

Macronutrient intake and estrogen metabolism in healthy postmenopausal women.

The purpose of this study was to determine if dietary factors could bias estimates of the relationships between estrogen metabolites and breast cancer risk factors. A lower ratio of urinary 2-hydroxyestrone/16alpha-hydroxyestrone (2/16) has been associated with breast cancer diagnosis. However, both estrogen metabolism and breast cancer risk have been associated with dietary intake, and breast cancer patients may have different dietary patterns than healthy controls. An association between urinary 2/16 levels and breast cancer risk may be due to transitory dietary change after diagnosis, or due to other breast cancer risk factors which have been associated to steroid hormone metabolism. Thirty-seven healthy postmenopausal women provided two 24-h urine samples at a two-week interval. Six 24-h diet recalls were administered in this same time period. In linear regression analysis, dietary fat-to-fiber ratio (fat/fiber) and the saturated fat/soluble fiber ratio was inversely associated with urinary 2/16 values (b = -0.22, 95% CI (-0.43, -0.01); b= -0.26, 95% CI (-0.43, -0.09), respectively). The effects of these dietary factors on 2/16 were independent of body mass index or other breast cancer risk factors. These study results suggest that some of the variation in estrogen metabolite levels among postmenopausal Caucasian women may be due to dietary intake, and that dietary factors should be carefully measured and evaluated when investigating the relationship between estrogen metabolites and breast cancer risk.

Aged↗

PubMed2001

Using isothiocyanate excretion as a biological marker of Brassica vegetable consumption in epidemiological studies: evaluating the sources of variability.

OBJECTIVE: Brassica vegetable consumption (e.g. broccoli) leads to excretion of isothiocyanates (ITC) in urine. We evaluated the consistency of ITC as a biomarker for dietary Brassica vegetable consumption across the types of vegetables and methods of preparation used in Western societies, and across consumption levels. DESIGN: A single-armed behavioural intervention with duplicate baseline assessment and post-intervention assessment. Urinary ITC excretion and estrogen metabolites were measured from 24-hour urine samples. Dietary intake was measured by a 24-hour recall. SETTING: The behavioural intervention facilitated daily Brassica intake among participants by providing peer support, food preparation instruction, guided practice in a teaching kitchen, and other information. SUBJECTS: Thirty-four healthy free-living postmenopausal women who recently had a negative screening mammogram at the University of Massachusetts Medical Center. RESULTS: Urinary ITC excretion and total Brassica intake followed the same pattern over the intervention. The ITC biomarker significantly predicted Brassica intake when Brassica consumption averaged about 100 g day-1, but not when Brassica consumption averaged about 200 g day-1. Urinary ITC levels were somewhat higher when more raw vegetables were consumed as compared to lightly cooked vegetables, while the types of Brassica consumed appeared to have only a small, non-significant effect on urinary ITC levels. CONCLUSION: Urinary ITC excretion would be a good exposure biomarker among populations regularly consuming a vegetable serving/day, but may be less accurate among populations with greater intake levels or a wide range of cooking practices.

Aged↗

PubMed2001

The macrobiotic diet in cancer.

Macrobiotics is one of the most popular alternative or complementary comprehensive lifestyle approaches to cancer. The centerpiece of macrobiotics is a predominantly vegetarian, whole-foods diet that has gained popularity because of remarkable case reports of individuals who attributed recoveries from cancers with poor prognoses to macrobiotics and the substantial evidence that the many dietary factors recommended by macrobiotics are associated with decreased cancer risk. Women consuming macrobiotic diets have modestly lower circulating estrogen levels, suggesting a lower risk of breast cancer. This may be due in part to the high phytoestrogen content of the macrobiotic diet. As with most aspects of diet in cancer therapy, there has been limited research evaluating the effectiveness of the macrobiotic diet in alleviating suffering or prolonging survival of cancer patients. The few studies have compared the experience of cancer patients who tried macrobiotics with expected survival rates or assembled series of cases that may justify more rigorous research. On the basis of available evidence and its similarity to dietary recommendations for chronic disease prevention, the macrobiotic diet probably carries a reduced cancer risk. However, at present, the empirical scientific basis for or against recommendations for use of macrobiotics for cancer therapy is limited. Any such recommendations are likely to reflect biases of the recommender. Because of its popularity and the compelling evidence that dietary factors are important in cancer etiology and survival, further research to clarify whether the macrobiotic diet or similar dietary patterns are effective in cancer prevention and treatment is warranted.

Diet, Macrobiotic↗

PubMed2001

Psychosocial stress and prostate cancer: a theoretical model.

African-American men are more likely to develop and die from prostate cancer than are European-American men; yet, factors responsible for the racial disparity in incidence and mortality have not been elucidated. Socioeconomic disadvantage is more prevalent among African-American than among European-American men. Socioeconomic disadvantage can lead to psychosocial stress and may be linked to negative lifestyle behaviors. Regardless of socioeconomic position, African-American men routinely experience racism-induced stress. We propose a theoretical framework for an association between psychosocial stress and prostate cancer. Within the context of history and culture, we further propose that psychosocial stress may partially explain the variable incidence of prostate cancer between these diverse groups. Psychosocial stress may negatively impact the immune system leaving the individual susceptible to malignancies. Behavioral responses to psychosocial stress are amenable to change. If psychosocial stress is found to negatively impact prostate cancer risk, interventions may be designed to modify reactions to environmental demands.

Black or African American↗

PubMed2000

Sources of variability in dietary intake in two distinct regions of rural India: implications for nutrition study design and interpretation.

OBJECTIVE: Limited inter-person variability in nutrient intake hampers epidemiologic studies of diet-disease relationships. Despite conjecture about non-traditional study bases providing large inter-person differences, virtually nothing is known about variations in nutrient intake outside of Europe and North America. The current study was conducted in India to determine sources of variability in the intakes of nutrients thought to be of public health importance. DESIGN: Adult subjects in Gujarat (North India; n=60) and in Kerala (South India, n=60) were administered 24 h diet recall interviews six and eight times, respectively, over a 1 y period. To assess subject (inter-person) and residual (intra-person) contributions to variance, regression models were fit to the data. From this, the variance ratio (VR, total within or intra-person: total between or inter-person) was computed. SETTING: Rural communities in North and South India. RESULTS: In both regions, inter-person variability was larger than that observed in the West. This was most pronounced in Gujarat, for which the VR was <1.0 for seven of the 12 energy-adjusted nutrient intakes in both men and women. In analyses of the combined data, region accounted for >20% of variance for fat, iron, copper, zinc, beta-carotene and riboflavin in both men and women. With the region term removed from this model, virtually all of the variability ascribed to region contributed to inter-person variability. CONCLUSIONS: The relatively large inter-person variability observed here could contribute to improved 'resolution' of diet-outcome relationships in epidemiologic studies. While this applies to data from each region, it was especially evident in analyses of the combined data.

Adult↗

PubMed2000

Comparing physical activity assessment methods in the Seasonal Variation of Blood Cholesterol Study.

PURPOSE: This paper evaluated three measures of physical activity employed in the Seasonal Variation of Blood Cholesterol Study (Seasons), and it had two objectives: 1) To examine the laboratory validity of the Actillume activity monitor, and 2) To examine the relative validity of three 24-h physical activity recalls (24HR) in quantifying short-term physical activity behaviors. METHODS: Nineteen healthy middle-age adults completed seven activity trials (reading, typing, box moving, stepping, and walking (3.5, 4.25, 5.0 km x h(-1))) while oxygen consumption and Actillume measures were obtained. ANOVA, linear regression, and a scatter plot were employed to examine the validity of the Actillume. In relative validity analyses of the 24HR in the Seasons study, participants (N = 481) completed two or three 24HR (MET-h x d(-1)) and a modified Baecke Questionnaire. A subset of the cohort (N = 41) wore the Actillume for 3-8 d (counts x min(-1) x d(-1)). The relative validity of the 24HR method was examined by comparison to these criterion measures. RESULTS: In laboratory validation analyses, the monitor was found to discriminate between sedentary and moderate intensity activities, changes in walking speed, and to account for 79% of the variance in oxygen consumption across sedentary and walking trials. In relative validity analyses, correlations between the 24HR and the modified Baecke ranged from 0.29 to 0.52 (P < 0.01) across total, household, occupational, and leisure-time activities. CONCLUSIONS: In laboratory testing, the Actillume monitor discriminated between sedentary and moderate intensity activities and was highly correlated with oxygen consumption. Three 24HR of physical activity were observed to have a relative validity that was comparable to published data from other short-term activity assessments that also employed the Baecke Questionnaire and activity monitors as criterion measures.

Adult↗