Nguyen will differ by the joint effects of the perception of mental health need and Asian ethnic background. Methods Data source This study uses data derived from the publicly available 2001 California Health Interview Survey (CHIS).10 The CHIS 2001 was selected for this study because of the availability of men- tal health need and service use variables that are not included in later versions of the California Health Interview Survey. The CHIS 2001 is a cross-sectional study of California residents’ health and access to health care services.11 A list- assisted random digit dial telephone survey, CHIS 2001 used a two-stage sampling procedure to generate represen- tative estimates throughout the state. Separate surveys were administered for children and adults. Advertising outreach was conducted to enhance the participation rate, with a focus on linguistic and cultural minorities. While Chinese and Filipino respondents were recruited from traditional probability sampling methods, oversampling methods were used with Korean and Vietnamese subgroups to increase sample sizes and enhance estimate precision. The survey was translated and administered in several Asian languages including Mandarin, Korean, and Vietnamese.12 A total of 57,848 adults responded to the phone survey. The CHIS 2001 sample design documentation reported an overall 38% response rate.11 For this study, data on self-identified Asian Americans from Chinese, Filipino, Korean, and Vietnamese backgrounds aged over 50 years were extracted from the CHIS. To increase the study’s ability to make inferences about specific Asian ethnic groups, respondents from other Asian ethnic groups were excluded due to limited observations. This yielded a study sample of 1191 Asian Americans. The protocol for this study was deemed exempt from full review by the local institutional review board. Measures The dependent measure for this study was the number of physician contacts. All respondents to CHIS 2001 were asked, “How many times have you seen a doctor about your own health in the past 12 months?” The study applied the behavioral model9 to organize covariates of physician visits. Predisposing characteristics were: age; Chinese, Filipino, Korean, and Vietnamese ethnicity; gender; and nativity, foreign or US born. Insurance status, English proficiency, and living arrangement were used as enabling covariates. 334 submit your manuscript | www.dovepress.com Dovepress Dovepress The study used perceived mental health, general health, and mental health specialist use as need factors. The General Health item from the Short Form-12 (SF-12) Health Survey13 was used as a measure of self-rated health. The Excellent, Very Good, and Good categories are very similar and were collapsed into one category as Good. The Fair/Poor responses were categorized as Fair. Two questions in CHIS 2001 related to mental health need and service use. The first asked for the respondents perceived mental health need: “During the past 12 months, did you think you needed help for emotional or mental health problems, such as feeling sad, blue, anxious or nervous?” The second asked, “Not counting overnight stays, emergency room visits, or visits for drug or alcohol problems, in the past 12 months, have you seen a psychiatrist, psychologist, social worker, or counselor for emotional or mental health problems?” Analyses Replicate weights were applied using SAS-callable SUDAAN 9.0.1 (RTI International, Research Triangle Park, NC) to account for the survey’s complex sampling methods. Chi-square tests were used to examine bivariate associations between categorical variables. Linear regres- sion was used to model the quantity of physician visits. Main effect and interactive models were tested to examine the moderating effects of the perception of mental health need by ethnic group. While Chinese and Vietnamese dif- fer in their migration experiences, many Vietnamese in the United States are ethnic Chinese, and both groups share a common belief system14 that is distinct from Koreans and Filipinos.15 Therefore, in an effort to focus on potential differences in cultural beliefs among the primary Asian ethnic groups, the Chinese and Vietnamese groups were combined as the reference category for the multivariate analysis. Results The weighted descriptive statistics are presented in Table 1. Overall, respondents had seen a doctor an average of 4.9 times in the previous 12 months; 7.0% perceived that they had a mental health need. The bivariate associations between the independent variables and the four Asian ethnic groups are presented in Table 2. The number of physician contacts ranged from a low of 4.1 for Chinese Americans to a high of 5.8 for Vietnamese Americans. One in five Vietnamese Americans perceived a mental health need, which was three times the frequency of any other group. Differences in the percentages of fair health Clinical Interventions in Aging 2010:5