Cervical cancer screening in BC Chinese women

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Introduction
Chinese immigration has increased dramatically in British Columbia in recent years. As of 1996, 299 860 (8%) of the BC population identified themselves as Chinese.[1] A large proportion (77%) were foreign born, coming mainly from East and Southeast Asia (Statistics Canada. Unpublished data. Ottawa, ON;1996). Invasive cervical cancer is an important health concern for Chinese women, being the second leading cause of cancer deaths in Mainland China.[2] Age-standardized cervical cancer incidence rates (per 100 000) have been reported approaching 20 for Chinese people in Hong Kong and Singapore and 12.3 for Chinese people in Los Angeles as compared to 7.2 for non-Hispanic white people in Los Angeles.[3] Asian-born US Chinese people have higher incidence rates than North American-born Chinese people. In BC, Chinese people have been found to have twice the cervical cancer risk of white people.[4] These differences in rates may in part reflect differences in Pap screening coverage, for the limited available data consistently shows lower cervical cancer screening rates for Asians as compared to white people.[4-11]

We are currently conducting a randomized controlled trial to evaluate the impact of a cervical cancer control intervention targeting the Chinese population in Vancouver and Richmond. The intervention includes culturally and linguistically appropriate written materials on Pap testing, a motivational video, and the services of an outreach worker. As part of this project, a community-based survey of Chinese residents was conducted in 1999 in order to obtain information about Pap screening barriers and facilitators for developing effective intervention strategies for Chinese women. This paper presents the sociodemographic factors that were associated both with ever having a Pap smear and with having a Pap smear within the last 2 years.

Method

Study sample
For the community-based survey, a representative sample of Chinese women was selected from Vancouver and Richmond neighborhoods with a high proportion of Chinese residents: Vancouver Old Chinatown (60% Chinese), East Vancouver (36% Chinese), and Richmond (33% Chinese) (Statistics Canada. Unpublished data. Ottawa, ON;1996). A comprehensive list of Chinese surnames, totaling 178 for BC, was derived from multiple data sources, including published articles, cancer registry data, Screening Mammography Program of BC data, and telephone books.[12,13] This surname list was then used to identify randomly selected households from the 1998 Vancouver telephone book. Nineteen hundred households were identified to be approached for interview.

Survey questionnaire
Survey items were adapted, where appropriate, from the Pathways to Prevention questionnaire, which has been used in several Asian-American populations.[9,14,15] In addition, women were asked whether they had ever had a Pap smear and, if so, whether they had been screened within the last 2 years. Women were also queried about their age, country of birth, religion, marital status, educational level, household income, housing type (owned, rented, government-subsidized), length of time living in North America, and fluency in spoken English. The survey questionnaire was developed in English, translated into Cantonese and Mandarin, back-translated to ensure lexical equivalence, reconciled, and pre-tested.[10,16]

Data collection and analysis
About 1 month before the start of the survey, the Chinese community was made aware of the study through radio announcements and articles in newspapers and newsletters serving the Greater Vancouver Chinese community. All selected homes were then sent an introductory letter, written in both Chinese and English. Eleven trained female Chinese interviewers, fluent in Cantonese, Mandarin, and English, then visited each household to identify eligible women and to conduct the personal interview in the language of the woman’s choice.

Women were eligible for interview if they were 20 years of age or older and spoke Cantonese, Mandarin, or English. When a household included two or more age-eligible women, the interviewer asked to speak to the oldest woman. However, if the oldest woman refused or was unavailable, the interviewer asked if a younger household member would complete the survey. The survey interviewers made at least five attempts (including daytime, evening, and weekend attempts) at contacting each household.

Two separate analyses were done, first comparing women who reported at least one prior Pap smear to those who had never been screened, and second, comparing women who reported receiving screening within the last 2 years to those who had not. The chi-square test and, when necessary, Fisher’s exact test were used to assess statistical significance in bivariate comparisons.[17] Unconditional logistic regression models were used to summarize the joint effects of sociodemographic factors on cervical cancer screening participation.[18]

Results
We contacted 1617 households, 81% being Chinese. The remainder were business addresses or the residents could not be contacted. We interviewed 822 Chinese women, which represented 62% of the reachable and eligible households. Women were excluded from analysis who reported a personal history of invasive cervical cancer, who were over age 79 years, and who had missing data on their Pap testing history; this left a final sample of 776 women.

Pap screening rate
Five hundred seventy-seven (74%) women reported that they had received at least one prior Pap smear, and 434 (56%) reported receiving a Pap smear within the last 2 years. Both ever and recently receiving a Pap smear were significantly related to age, with the lowest rates for the oldest age group (Figure 1a).

Sociodemographic factors associated with Pap testing
In addition to age, the following factors were also associated with both ever having received a Pap smear and recently receiving a Pap smear within the last 2 years: place of birth, marital status, education, fluency in English, household income, and household type (Figures 1a and 1b).

The proportion of life spent in North America and previous hysterectomy were associated with ever being screened and recently being screened, respectively. Religion was not associated with Pap testing. All associated factors were significant at p<0.001 except for place of birth in women ever being screened (p = 0.04) and speaking English fluently in women being screened recently (p = 0.002).

Pap screening rates were lowest for women from Mainland China, who never married, with the lowest education, no fluency in English, lowest household income, and living in subsidized housing. In addition, women with shorter time in North America were less likely to have been ever screened, and those with a previous hysterectomy were less likely to have been screened within the last 2 years.

Logistic regression analysis identified age, place of birth, marital status, household type, proportion of life in North America, and fluency in English as independent factors associated with a history of receiving at least one Pap test (Table 1). Age, place of birth, marital status, household type, and previous hysterectomy were independently associated with recent Pap testing within the last 2 years (Table 2).

Discussion
Our community-based survey found that 74% of Chinese women had at least one previous Pap smear and 56% had a smear within the last 2 years. This latter proportion compares to the BC provincial average of 67% for women aged 20 to 69 years being screened at least once between July 1996 and December 1998.[19] Other investigators have also reported lower rates of screening in the Asian population.[4-11]

Several sociodemographic factors were associated with Pap testing. Lower rates of Pap testing were found for older women, those never married, from Mainland China, with a shorter duration of time in North America, not fluent in English, with lower education and household income, and living in subsidized housing. Women with a previous hysterectomy were less likely to have been screened recently.

The age difference in the screening rates for Chinese women (with lowest rates in the oldest age group) is not surprising for recent screening as the oldest group includes women in their 70s for which screening is generally not recommended. However, this does not explain the low rate for having ever received a Pap test. The observation of lower cervical cancer screening rates with advanced age has been found in other studies of the BC population.[20,21]

Women who have never or have previously been married were less likely to be screened than currently married women. They may be of the impression that they are not at risk of cervical cancer; however, according to the current basic screening guidelines, all women who have been sexually active should be screened regularly.[19]

The proportion of life spent in North America and fluency in English indicate in part the level of acculturation into the Canadian population. Women with less acculturation may be less aware of Pap testing and the resources available to them for health care. Lower education and household income may compound these difficulties. There is the need for better education about the value of regular Pap screening in ways that are culturally appropriate.

This study has several limitations. First, self-reporting of Pap testing history may be inaccurate among this study group. However, in a study of Korean Americans, the test-retest reliability was found to be high for ever having had a Pap smear and for timing of the last smear.[10] Second, the relatively low response rate may have introduced response bias.

Although the study interviewers were very diligent in trying to make personal contact with the randomly selected households, this sometimes was not possible. When contact was made, the interviewer tried to accommodate the woman as to suitability of the time for interview. It is not clear to what extent the survey respondents may differ from those who refused to be interviewed; however, it is quite likely that those who refused an interview were less likely to be receiving cervical cancer screening.

In conclusion, our study has provided information about cervical cancer screening in Chinese women in the Vancouver area. Pap screening rates are lower than the provincial average. Information on the barriers and facilitators to Pap testing as reported by the respondents to the survey has been used to develop culturally appropriate educational materials that are currently being evaluated in a randomized controlled trial.

Acknowledgments
We wish to thank the women who participated in these interviews; the interviewers: C. Chan, I. Chan, L. Hsu, A. Ko, S. Leung, M. Li, J. Ng, E. Ng, C. Pang, G. Troung; the community advisory coalition: I. Chan and L. Lai (Canadian Cancer Society), Dr J. Ko (Taiwanese Canadian Cultural society), G. Mumick (Vancouver-Richmond Health Board), S. Leung (SUCCESS), Dr L. Sent (Asian Women’s Health Clinic), Dr C. Wang (Chinese Canadian Medical Society), Dr M. Yu (Chinese Cultural Centre); other members of the research team: Dr C. Jackson, Dr S.-P. Tu, Dr Y. Yasui, Dr S. Schwartz, A. Kuniyuki; and E. Fowler for preparing the manuscript. This work was supported by the US National Cancer Institute and the British Columbia Health Research Foundation.

Dr Hislop is senior epidemiologist, Cancer Control Research, BC Cancer Agency, and clinical professor, Department of Health Care and Epidemiology, University of British Columbia. Dr Teh and Ms Labo are project coordinators, Cancer Control Research, BC Cancer Agency. Ms Lai is research assistant, Cancer Control Research, BC Cancer Agency. Dr Taylor is associate member, Division of Public Health Services, Fred Hutchinson Cancer Research Center, Seattle, Washington.