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author:("Chen, chute")
1.  Reliability of RT3 Accelerometers Among Overweight and Obese Adults 
Purpose
Accurate and reliable measurement of physical activity plays an important role in assessing effective lifestyle interventions for obesity. This study examined reliability of accelerometer-based estimates of physical activity levels of overweight and obese adults before and after a lifestyle weight loss program.
Methods
Participants were overweight and obese (BMI 25–45 kg/m2) members (n=1592; 67% female, 42% African American) of the multi-center Weight Loss Maintenance trial. They wore RT3 accelerometers during waking hours for 7 days at baseline and after a 6-month weight loss intervention that included diet and physical activity recommendations. Moderate to vigorous physical activity (MVPA) and MVPA occurring in bouts ≥ 10 minutes (bout MVPA) were assessed.
Results
At baseline, wear time minimums of 10 and 6 hours/day resulted in similar average minutes·day−1 of MVPA (18.3 and 18.0 minutes) and MVPA bout minutes·day−1 (6.9 and 6.7 minutes). Similar wear times occurred after the weight loss intervention for MVPA (27.0 and 26.8 minutes) and bout MVPA (15.1 and 15.0 minutes). Reliability measurements by Intra Class Correlation (ICC) were larger for 4 versus 2 days·week−1 minimum wear time for both MVPA and bout MVPA (4 day ICCs .27–.44 and 2 day ICCs .19–.38), but there was little increase in ICC comparing 4 (ICCs.27–.44) and 7 days·week−1 (ICCs .30–.46).
Conclusions
Longer wear time requirements did not result in significant increases in reliability. Using 4 days of data with ≥ 6 hours·day−1 of wear time optimized the balance between ICC and participant burden in overweight and obese adults before and after a weight loss intervention. Future investigations using accelerometers to estimate MVPA in overweight and obese samples can consider requiring less monitor wear time.
doi:10.1249/MSS.0b013e3181846cd8
PMCID: PMC3700541  PMID: 19092700
Physical Activity; Exercise; Bouts; Ambulatory Monitoring; Measurement
2.  US acculturation is associated with health behaviors and obesity, but not their change, with a hotel-based intervention among Asian-Pacific Islanders 
Background
Immigration to the United States has been associated with obesity, yet the relationship of acculturation with obesity and energy balance (i.e., physical activity/dietary intake) in adults is a complex issue. Limited longitudinal data is available on immigrant Asians and Pacific Islanders.
Design
Analyses were conducted on baseline data and change data from baseline to 24 months in the hotel-based cluster-randomized Work, Weight and Wellness (3W) trial involving 15 control and 15 intervention hotels on the island of Oahu, Hawaii.
Sample
Participants were adult employees of predominantly Asian and Pacific Islander ancestry who were assessed one or more times over the course of 24 months. The full sample consisted of 4236 hotel workers (about 40% of hotel workforce) at baseline, 3502 hotel workers at year one and 2963 hotel workers at the 24-month follow up. 1115 hotel workers had at least two measurements, and were included in the analysis.
Intervention
The 3W intervention was designed to promote weight loss via motivation and support for increases in physical activity and increased access to and consumption of healthy low fat/low calorie foods. The measure of acculturation consisted of a score that was a compilation of a participant’s age when he or she immigrated to the US/Hawaii, country of birth, language spoken at home, and years of education.
Statistical Analyses
We used mixed effect regression models for cross-sectional baseline models and longitudinal multilevel regression analysis of change in diet and physical activity behaviors and obesity over time using a fixed intercept. Estimates of the intervention effect are expressed as an annual rate of change for all study outcomes.
Results
At baseline acculturation was positively associated with body mass index, physical activity level; and fruit, meat, and sweetened drink intake level. In analyses of change over 24-months, acculturation did not significantly influence change in dietary intake or indices obesity (i.e. BMI or waist/height ratio). However physical activity increased significantly more in the intervention group, over the course of the intervention, compared to the control group, which decreased activity, controlling for socio-demographic factors (including acculturation) and food intake behavior
doi:10.1016/j.jand.2012.02.002
PMCID: PMC3378986  PMID: 22709769
3.  Glycemic index and glycemic load are associated with some cardiovascular risk factors among the PREMIER study participants 
Food & Nutrition Research  2012;56:10.3402/fnr.v56i0.9464.
Background
The clinical significance of glycemic index (GI) and glycemic load (GL) is inconclusive.
Objective
This study was conducted to examine the association of GI and GL with clinical cardiovascular disease (CVD) risk factors including body weight, blood pressure (BP), serum lipids, fasting glucose, insulin and homocysteine over time among the PREMIER participants.
Design
PREMIER was an 18-month randomized lifestyle intervention trial, conducted from 2000 to 2002, designed to help participants reduce BP by following the Dietary Approaches to Stop Hypertension (DASH) dietary pattern, losing weight, reducing sodium and increasing physical activity. GI and GL were estimated from 24 h diet recall data at baseline, 6 and 18 months after intervention. PROC MIXED model was used to examine the association of changes in GI or GL with changes in CVD risk factors.
Results
A total of 756 randomized participants, 62% females and 34% African Americans and who averaged 50.0±0.3 years old and 95.3±0.7 kg, were included in this report. Neither GI nor GL changes was associated with changes in any risk factors at 6 months. At 18 months, however, the GI change was significantly and positively associated with total cholesterol (TC) change only (p<0.05, β=23.80±12.11 mg/dL or 0.62±0.31 mmol/L) with a significant age interaction. The GL change was significantly associated with TC (p=0.02, β=0.28±0.15 mg/dL or 0.01±0.00 mmol/L) positively and with low density lipoprotein cholesterol (LDL-C) changes negatively (p=0.03, β=−0.01±0.00 mg/dL or −0.00±0.00 mmol/L), and significant age interactions were observed for both.
Conclusions
GI and GL was associated with TC and LDL-C after controlling for energy, fat and fiber intake and other potential confounders and the associations were modified by age. Further investigation into this relationship is important because of its potential clinical impact.
doi:10.3402/fnr.v56i0.9464
PMCID: PMC3368490  PMID: 22675288
glycemic index; glycemic load; diet; cardiovascular risk
4.  Biobank Recruitment: Motivations for Nonparticipation 
Biopreservation and Biobanking  2009;7(2):119-121.
Molecular data, essential for genomics research, can be captured more efficiently in large-scale, population-based biobanks of genetic material rather than by individual studies. Biobanks also offer improved quality and reliability of genetic samples and access through automated sample retrieval. However, it is challenging to adequately inform participants of the broad nature of the research and participation risks and benefits. In addition, recent studies suggest concerns about data sharing and return of research results, or future research topics (eg, stereotypical or potentially stigmatizing traits). We evaluated the interest in participating in a biobank and reasons for nonparticipation.
doi:10.1089/bio.2009.0006
PMCID: PMC3205734  PMID: 22087353
5.  Patterns of Physical Activity Among Overweight and Obese Adults 
Preventing Chronic Disease  2009;6(3):A90.
Introduction
Little is known about patterns of physical activity in overweight and obese adults, although they are at high risk for chronic disease and can benefit from physical activity. We describe patterns of moderate-to-vigorous physical activity (MVPA) and MVPA in bouts of 10 minutes or longer in overweight and obese adults.
Methods
Overweight and obese participants (n = 1,648) who were screened for the multicenter Weight Loss Maintenance Trial wore RT3 accelerometers for at least 3 weekdays and 1 weekend day. We determined minutes spent in moderate physical activity, vigorous physical activity, and MVPA overall, by weekday vs weekend, and by time of day. We also measured bouts of at least 10 minutes of sustained MVPA.
Results
Participants were active for an average of 15.8 minutes per day. Among those who engaged in bouts of MVPA, the average bout was 33.3 minutes long. Participants who were younger than 50 years, male, non-African American, or overweight were more active than were those who were older than 50, female, African American, or obese. Participants were more active on weekends than on weekdays and in the morning than in the afternoon or evening. Only 2% of participants were active for 60 or more minutes per day.
Conclusion
We found differences in physical activity patterns by demographic characteristics, day, and time of day. Weekend mornings may be an opportune time to promote additional physical activity.
PMCID: PMC2722396  PMID: 19527591
6.  Performance of the U.S. Office of Management and Budget’s Revised Race and Ethnicity Categories in Asian Populations* 
Objectives
The U.S. Office of Management and Budget (OMB) guidelines for collecting and reporting race and ethnicity information recently divided the “Asian or Pacific Islander” category into “Asian” and “Native Hawaiian or Other Pacific Islander”. The OMB’s decision to disaggregate the “Asian or Pacific Islander” category was the first step toward providing these communities with information to better serve their needs. However, whether individuals who formerly made up the combined group categorize themselves as the new guidelines intend is a question analyzed in this report.
Methods
A subset of adults participating in the Hemochromatosis and Iron Overload Screening Study completed both the OMB-minimum and the expanded race and ethnicity measure used in the National Health Interview Survey. We compared responses on the expanded measure contained within the OMB “Asian” definition (Filipino, Korean, Vietnamese, Japanese, Asian Indian, Chinese, and/or Other Asian) to “Asian” responses on the OMB-minimum measure.
Results
Mixed heritage Asians less often marked “Asian”. Among mixed heritage Japanese, Chinese, and Filipinos, 27%, 49%, and 52% did not mark “Asian” on the OMB measure, respectively. Eleven percent of single-heritage Filipinos did not mark “Asian.”
Conclusions
Many individuals formerly making up the combined “Asian or Pacific Islander” group do not categorize themselves as the revised OMB guidelines intend. This is particularly evident among Filipinos and among Asians of mixed heritage. This research illuminates the reliability and utility of the broad “Asian” category and points to possible consequences of collapsing groups into a single category, i.e., missed information and/or erroneous generalization.
doi:10.1016/j.ijintrel.2007.02.001
PMCID: PMC2084211  PMID: 18037976

Results 1-6 (6)