The California Health Interview Survey (CHIS) is a random-digit-dial telephone survey conducted biannually to provide population-based estimates for California.20
CHIS is the largest telephone survey in California and the largest state health survey in the US. A two-stage, geographically-stratified design was utilized in an effort to produce a representative sample of California adults (http://www.chis.ucla.edu
). At stage one, a random sample of telephone numbers was computer-generated for 44 predefined geographic areas and screened for eligibility. At stage two, one adult aged 18+ years from each of the ~44,500 households was randomly selected to be interviewed on fourteen health-related topics via a computer-assisted telephone interviewing system. CHIS interviewers completed ~12 hours of training on interviewing techniques and the computer-assisted protocol, and were monitored throughout data collection for quality control. Pilot testing revealed that mean completion time for the entire interview was 39.2±8.8 minutes. Demographic and health behavior sections were completed in 2.5±1.2 and 8.1±2.4 minutes, respectively, which included additional variables not analyzed in the present study. The overall response rate was 29.2%.
Demographic (gender, highest level of education, annual household income), body mass index (BMI) and health behavior (tobacco use, dietary intake, leisure-time physical activity) variables were retrieved from the 2005 CHIS for individuals who self-identified as NHPI or WH, according to US Census 2000 definitions.21
Education levels were categorized ranging from ‘no formal education’ to ‘at least a Bachelor’s degree’ and mean annual household income was reported as a continuous variable. NHPI ethnicity was defined as “any person having origins in any of the original peoples of Hawaii, Guam, Samoa, or other Pacific Islands”, and included ‘Native Hawaiian’, ‘Guamanian or Chamorro’, ‘Samoan’, and ‘Other Pacific Islander’ races. The WH sample was defined as “any person having origins in any of the original peoples of Europe, the Middle East, or North Africa”, and included individuals who indicated their race as "White" or reported entries such as Irish, German, Italian, Lebanese, Near Easterner, Arab, or Polish. The NHPI sample was analyzed collectively, rather than being disaggregated into subgroups, due to the small sample size. All data were presented for NHPI and WH groups, and by gender.
Tobacco use questions on the CHIS 2005 were standard smoking questions used by the U.S. Census Bureau, National Cancer Institute and the Centers for Disease Control and Prevention. Although validity and reliability have not been reported, these questions are similar to those used in the California Tobacco Surveys since 1990.22,23
Respondents who had smoked 100+ cigarettes in their lifetime were classified as ‘ever smokers’. Current smoking behavior of ‘ever smokers’ further classified individuals as either ‘former’ or ‘current’ smokers. Current smokers reported the average number of cigarettes they smoked per day.
Dietary intake questions asked respondents to think about all the foods and beverages consumed in the past month, including meals and snacks. Consumption of specific foods, similar to the Behavioral Risk Factor Surveillance System questions (www.cdc.gov/brfss/questionnaires/questionnaires.htm
) that report moderate validity and test-retest reliability,24
were reported as ‘per week’ and answers were converted to servings per day. F&V consumption included fruit, 100% fruit juices, potatoes, beans, salads and vegetables, and respondents consuming at least five daily servings were categorized as ‘meeting F&V guidelines’. Unhealthy food consumption included sodas, fruit-flavored drinks, fries, ice cream/frozen desserts and cakes/pies/cookies, and a sum score of servings per day was computed.
The physical activity questions originated from the National Health Interview Survey (www.cdc.gov/nchs/nhis.htm
) and were adapted for telephone administration. Leisure-time physical activity included exercise, sports and physically active hobbies performed for at least 10 minutes during one’s leisure time. They were categorized as moderate-intensity, vigorous-intensity or resistance training. Although not validated, the classifications resulting from these questions are consistent with the recommendations set forth for adults in the Healthy People 2010 Objectives. Moderate-intensity activities were defined as those causing light sweating or a slight to moderate increase in breathing or heart rate and included walking for transportation (to get some place such as work, school, a store, or restaurant) and walking for fun (including walking for relaxation, exercise, or walking a dog). Vigorous-intensity activities included those that caused heavy sweating or large increases in breathing or heart rate (e.g., jogging, aerobic dance), and resistance training was defined as activities performed specifically to improve or maintain muscular strength or endurance (e.g., lifting weights or doing calisthenics).
Average duration (min/day) and frequency (days/week) reported for moderate- and vigorous-intensity activity were multiplied to calculate weekly durations (min/week), which were then summed to calculate total weekly physical activity (min/week). The proportion of respondents meeting current physical activity guidelines was determined for moderate-intensity (≥150 min/week), vigorous-intensity (≥75 min/week), the combination of both moderate- and vigorous-intensity activity (≥150 min/week) and resistance training (≥2 days/week).25
Guidelines for health behaviors were based on Healthy People 2010 objectives19
or the United States Department of Health and Human Services physical activity guidelines.25
Mean BMI values, calculated from self-reported height and weight, categorized respondents as ‘normal weight’ (≤25.0 kg/m2
), ‘overweight’ (25.0–29.9 kg/m2
), or ‘obese’ (≥30.0 kg/m2
Data analyses conducted in SPSS v17.0 included independent t-tests and Pearson Chi-Square to examine ethnic and NHPI gender differences for continuous and categorical variables, respectively. Binary logistic regressions were used to investigate associations between socio-demographic correlates of NHPIs meeting health behavior guidelines and to examine ethnic differences in obesity and smoking habits while controlling for education and income. Hierarchical linear regression was used to investigate ethnic differences in unhealthy food consumption and number of cigarettes smoked while controlling for education and income.