homework

Smoking-Adjusted Lung Cancer Incidence among Asian-Americans (United States)

Author(s): Meira Epplein, Stephen M. Schwartz, John D. Potter and Noel S. Weiss

Source: Cancer Causes & Control , Nov., 2005, Vol. 16, No. 9 (Nov., 2005), pp. 1085-1090

Published by: Springer

Stable URL: https://www.jstor.org/stable/20069562

REFERENCES Linked references are available on JSTOR for this article: https://www.jstor.org/stable/20069562?seq=1&cid=pdf- reference#references_tab_contents You may need to log in to JSTOR to access the linked references.

JSTOR is a not-for-profit service that helps scholars, researchers, and students discover, use, and build upon a wide range of content in a trusted digital archive. We use information technology and tools to increase productivity and facilitate new forms of scholarship. For more information about JSTOR, please contact [email protected]. Your use of the JSTOR archive indicates your acceptance of the Terms & Conditions of Use, available at https://about.jstor.org/terms

Springer is collaborating with JSTOR to digitize, preserve and extend access to Cancer Causes & Control

This content downloaded from �������������130.212.18.96 on Thu, 30 Sep 2021 03:18:27 UTC�������������

All use subject to https://about.jstor.org/terms

Cancer Causes and Control (2005) 16:1085-1090 DOI 10.1007/sl0552-005-0330-6

? Springer 2005

Smoking-adjusted lung cancer incidence among Asian-Americans (United States)

Meira Epplein1'2'*, Stephen M. Schwartz2'3, John D. Potter1'2 & Noel S. Weiss2'3 1 Cancer Prevention Program, Division of Public Health Sciences, Fred Hutchinson Cancer Research Center, 1100

Fairview Avenue N, M4-B402, P.O. Box 19024 Seattle, WA, 98109-1024, USA; 2Department of Epidemiology, University of Washington, Seattle, WA, USA; * Epidemiology Program, Division of Public Health Sciences, Fred Hutchinson Cancer Research Center, Seattle, WA, USA

Received 24 January 2005; accepted in revised form 13 May 2005

Key words: Asian Americans, lung cancer, smoking.

Abstract

Objective: Chinese women residing in Asia and Hawaii have low consumption of tobacco but a high incidence of lung cancer. To explore this question further, we conducted a study of lung cancer among Chinese women residing in mainland US.

Methods'. Using data from NCI's SEER program, we identified residents of Los Angeles County, the San Francisco Metropolitan Area, and the Seattle-Puget Sound Area who were 50 years or older, diagnosed with cancer of the lung or bronchus in 1999-2001, with race specified as non-Hispanic white (n = 18,493), Chinese (n = 853), Fili pino (n = 615), or Japanese (n = 282). The sex-specific observed number of lung cancer cases among each Asian sub-group was compared to the expected number of lung cancer cases for each Asian sub-group. The expected number was determined by multiplying the age-, sex-, and geographic area-adjusted incidence rates for non Hispanic whites by the age- and sex-specific ratio of percentage of current smokers in each Asian sub-group to whites in 1990, and then by the size of the respective Asian populations. Results'. Chinese women had a four-fold increased risk of lung cancer, and Filipino women a two-fold increased risk, compared to that expected based on rates in US non-Hispanic whites with a similar proportion of cigarette smokers. Lung cancer among Chinese, Filipino, and Japanese males, as well as Japanese females, did not deviate from expected risk. Among Chinese women, the increased risk was largely restricted to adenocarcinoma and large cell undifferentiated carcinoma.

Conclusions'. Chinese female residents of the western US mainland have a much higher risk of lung cancer than would be predicted from their tobacco use patterns, just as they do in Asia.

Introduction

Considering their relatively low use of tobacco products, Chinese women residing in Asia and Hawaii have a high incidence of lung cancer [1-5]. In broad terms, there are two potential explanations for this: (1) Chinese women have unusually marked susceptibility to the adverse

effects of cigarette smoke; or (2) Chinese women have a relatively high level of exposure to other lung carcino gens. Because the relative risk of lung cancer associated with smoking is similar in Chinese women and Chinese men, [1, 3-7] the second hypothesis appears stronger. Previous studies have examined lung cancer in Chinese women in Asia and Hawaii in relation to a number of potential exposures, including dietary factors [1, 4, 8, 9] hormonal factors [4, 9, 10] air pollution from smoky coal [11, 12] and heated unrefined cooking oils and fumes from meat cooking [13-16]. However, the causes of the excess incidence seen in these women remain unclear.

* Address correspondence to: Meira Epplein, Division of Public Health Sciences, Fred Hutchinson Cancer Research Center, 1100 Fairview Avenue N, M4-B402, P.O. Box 19024, Seattle, WA 98109 1024, USA. Ph.: +1-206-667-6034; Fax: +1-206-667-7850; E-mail:

mepplein @ fhcrc.org

This content downloaded from �������������130.212.18.96 on Thu, 30 Sep 2021 03:18:27 UTC�������������

All use subject to https://about.jstor.org/terms

1086 M. Epplein et al.

Studies to determine whether anomalously high lung cancer incidence is present among Chinese women who reside outside of Asia and Hawaii could shed further light on the causes of the disease. We sought to address this question by analyzing data from population-based cancer registries and surveys of smoking behavior in Asian Americans.

Methods

Study population

The focus of the study was lung cancer incidence among Chinese, Japanese, and Filipino residents of Los Angeles County, the San Francisco Metropolitan Area (Alameda, Contra Costa, Marin, San Francisco, and San Mateo counties), and the Seattle-Puget Sound Area (the 13 counties of Western Washington) in 1999-2001. Using the National Cancer Institute's Surveillance,

Epidemiology, and End Results (SEER) program database [17], we identified residents of the designated areas above who were 50 years or older, of known race, and diagnosed with cancer of the lung or bronchus in 1999-2001. The SEER Program began in 1973, collect ing race-specific data on cancer incidence in several US states and geographically defined metropolitan areas; at present, approximately a quarter of the US population is covered by registries participating in the SEER pro gram. Denominator data were obtained from the 2000 US Census [18]. As the 2000 Census allowed more than one race to be reported for each individual, analyses were conducted separately using two methods of esti mating the population-at-risk: (1) among persons who responded to the question of race/ethnicity as being of a particular, single race (e.g., Chinese); and (2) among persons who responded to the race/ethnicity question as being of a particular race either alone or in combination with any other race. The resulting estimated rates turned out to be nearly identical for the two methods of calculating the population-at-risk, and thus the results of this paper are based on the incidence rates using persons who responded to the question of race/ethnicity as being of a single race, since in the SEER data only a single race is listed.

Race-specific smoking prevalence data were obtained from the California Department of Health Services' 1992 report on tobacco use in California [19]. That report presents the findings of a University of California at San Diego telephone survey, conducted in 1990 and 1991, of adults throughout the state, selected by ran dom-digit dialing, and includes self-reported current smoking prevalence by race, age, and sex. These data

were chosen for this study because they are the most detailed data available on smoking prevalence by Asian racial/ethnic sub-group.

Data analysis

Sex- and age-specific observed lung cancer incidence rates for non-Hispanic whites were determined by dividing the number of cases in each five-year age group by the population-at-risk, in each geographic area. We sought to calculate the number of lung cancer cases expected among each Asian sub-group if the sub-group had experienced the same rate of lung cancer as non Hispanic whites, adjusted for age, geographic region, and relative smoking prevalence, separately for males and females. To do this, we first multiplied the age (in five-year age groups from 50 to 84 years, along with a final category of 85 years and older) and geographic area-specific incidence rates among non-Hispanic whites by the age-specific (categorized as 25-44, 45-64, and 65 +years) ratio of percentage of current smokers in each Asian sub-group to whites in 1990. The resulting figures represent estimates, for males and females, of age and geographic area-specific incidence rates among non Hispanic whites that would have been observed if they had smoked at the respective Asian levels. We then applied these estimated rates to the age and geographic area-specific Asian populations, by sex, to produce the expected number of lung cancer cases for each Asian sub-group.

The sex-specific risk of lung cancer for each Asian sub-group, compared to non-Hispanic whites, was then determined by dividing the observed number of lung cancer cases by the expected number. The 95% confi dence interval (CI) on each observed-expected ratio was calculated using Silcock's exact procedure based on the Binomial/Incomplete Beta for data where the expected estimate is not error free [20, 21]. Lung cancers were classified as to histologie types according to the Inter national Classification of Disease - Oncology (ICDO) [22] as follows: large cell undifferentiated carcinoma (ICDO 8012, 8013, 8020-8022, 8030, 8031), small cell carcinoma (ICDO 8040-8045), squamous cell carcinoma (ICDO 8032, 8050-8076), and adenocarcinoma (ICDO 8140, 8211, 8230, 8231, 8250-8254, 8260, 8310, 8323, 8480-8490, 8550, 8560, 8570-8572).

Results

Included in this analysis were a total of 18,493 non-Hispanic white, 853 Chinese, 615 Filipino, and 282 Japanese residents of three areas of mainland US with

This content downloaded from �������������130.212.18.96 on Thu, 30 Sep 2021 03:18:27 UTC�������������

All use subject to https://about.jstor.org/terms

Smoking-adjusted lung cancer incidence 1087

Table 1. Numbers of cases of primary lung cancer in three western US populations (Los Angeles County, San Francisco Metropolitan Area, Seattle-Puget Sound Area), 1999-2001

Los Angeles county

Males Females

San Francisco metro- Seattle-Puget Sound Total politan area area

Males Females Males Females Males Females

Non-Hispanic White 3757 3510 2151 2159 3602 3314 9510 8983 Chinese 212 158 286 157 24 16 522 331 Filipino 222 101 161 76 40 15 423 192 Japanese 101 75 34 30 18 24 153 129

cancer of the lung or bronchus (see Table 1 for the dis tribution of cases by geographic area). Smoking preva lence data showed that a smaller proportion of Asian women, of each racial/ethnic sub-group and age category, were current smokers than their counterpart non-His panic white women, whereas the age-specific smoking prevalence among male Asian racial/ethnic sub-groups was similar to that of non-Hispanic white men (Table 2).

Chinese women had a four-fold higher risk of lung cancer than expected based on age, geographic region, and smoking prevalence (Table 3). Filipino women had a two-fold higher risk than expected. In contrast, Filipino men, Chinese men, Japanese men, and Japanese women did not experience any appreciable difference in risk from that expected. The higher risk for Chinese women was present at all three geographic sites.

Among Chinese women, the risks of adenocarcinoma and large cell undifferentiated carcinoma were elevated six- and four-fold, respectively, whereas there was no difference in the risk of small cell carcinoma and, at most, a modest elevation of the risk of squamous cell carci noma (Table 4). In Filipino women, the only appreciably higher lung cancer risk was for adenocarcinoma.

Discussion

The most direct way of assessing smoking-adjusted incidence of lung cancer by race would be by means of a

multi-racial cohort study in which data on smoking status are obtained at baseline. To our knowledge, there are no published results from such a study. Therefore, to address the issue of whether there is excess lung cancer considering smoking prevalence among Chinese women in the US, we were obliged to pursue an indirect ap proach, using data on smoking among Asians external to our data on cancer incidence. There are a number of limitations to this approach that must be considered.

In the data obtained by the California Department of Health Services [23], smoking status was categorized simply as current versus other, with no data on dura tion, intensity, or recency of smoking. If Chinese or Filipino women who smoke cigarettes are unlike non Hispanic white women in any of these aspects of smoking behavior, our results could be biased. The prevalence data were also collected over the phone, by self-report, and may have been misreported, although we have no reason to believe this would vary among the racial/ethnic groups. Figures for smoking prevalence similar to those used in the present analysis were ob tained for Chinese men and women living in Oakland, California in 1989-1990 [23]. The prevalence data (whether from Oakland or California as a whole) ob tained approximately ten years prior to the diagnoses of lung cancer would seem to be a fairly reasonable choice in terms of characterizing risk. Nonetheless, if smoking behavior in any of the populations studied has changed considerably during the past several decades, the use of

Table 2. Prevalence (%) of current cigarette smoking among white and Asian Californians, by age and sex, 1990-199Ia

Males Females

25-^4 years

Ratio to Whites

45-64 years

Ratio to Whites

65 + years

Ratio to Whites

25-44 years

Ratio to Whites

45-64 years

Ratio to Whites

65 + years

Ratio to Whites

Non-Hispanic White 27.9 1.00 25.5 1.00 13.0 1.00 24.1 1.00 23.8 1.00 12.5 1.00 Chinese 20.9 0.75 19.9 0.78 19.8 1.52 5.5 0.23 2.5 0.11 2.6 0.21

Filipino 29.2 1.05 25.8 1.01 10.6 0.82 14.6 0.61 5.1 0.21 3.4 0.27 Japanese 24.7 0.89 22.1 0.87 11.1 0.85 16.3 0.68 13.4 0.56 8.3 0.66

Source: Burns D, Pierce JP. Tobacco Use in California 1990-1991. Sacramento: California Department of Health Services, 1992.

This content downloaded from �������������130.212.18.96 on Thu, 30 Sep 2021 03:18:27 UTC�������������

All use subject to https://about.jstor.org/terms

1088 M. Epplein et al.

Table 3. Observed lung cancer cases versus those expected,a based on smoking prevalence, among Asians in three western US populations (Los Angeles county, San Francisco metropolitan area, Seattle-Puget Sound area), adjusted for age and geographic region, 1999-2001

Males Females

Observed cases Expected casesa Relative risk (95% CI) Observed cases Expected casesa Relative risk (95% CI)

Chinese 522 632.6 0.8(0.7-0.9) 331 82.3 4.0(3.2-5.1) Filipino 423 331.5 1.3(1.1-1.5) 192 96.3 2.0(1.6-2.6) Japanese 153 190.7 0.8(0.6-1.0) 129 145.8 0.9(0.7-1.1)

a Calculated by multiplying the age-specific incidence rate in non-Hispanic whites by the age-specific ratio of smoking prevalence of whites to each Asian sub-group, and the total then multiplied by the respective age-specific Asian sub-group population-at-risk.

data at a single point in time may provide a misleading idea of that population's smoking-related burden of lung cancer. Other limitations are related to those present in our

sources of data. Regarding accuracy in the reporting of histologically defined subsets of cancer, a recent study compared reported histologie codes for lung cancer in the SEER registry with an independent review of diag nostic slides, and found reasonably good agreement [24]. The potential for inaccuracy and the inconsistency in the way in which race information is collected by the SEER program (i.e., relying largely on medical records) could lead to misclassification of some cases, particularly

within the Asian sub-groups. In addition, we were un able to provide rates of lung cancer in Asian-American women according to country of birth and, if foreign born, age at migration to the US. Of the Chinese women whose country of birth was recorded in the SEER data files, 85-90% were born outside of the US, and so our results may well not portray the experience of American-born Chinese women.

Noting these limitations, our finding of increased risk of adenocarcinoma and large cell undifferentiated car cinoma of the lung among Chinese women in mainland United States, who have a low prevalence of smoking, is consistent with what has been found among Chinese women in Asia and Hawaii [1, 3, 25-28]. Although there has been no examination of potential lung carcinogens, other than cigarette smoke, that might account for the high rate among Chinese women in the US mainland, a number of studies have examined such possible expo sures among Chinese women in Asia.

Case-control studies in northeast [29] and southeast [12, 30, 31] China have observed an increased risk of lung cancer (odds ratios of 1.5-5.8) among non smoking Chinese women associated with heating coal indoors or indoor exposure to coal smoke. Among women with more than 30 years use of a coal stove in the bedroom, the odds ratio was 18.8 (95% CI 3.9-29.3) in the northeast city of Harbin [29]. However, two other case-control studies - one in the north and

one in the south of China - found no association between indoor exposure to coal smoke and lung cancer [14, 32].

Results of examinations of unrefined cooking oils have been more consistent, with all studies observing some excess risk (relative risks of 2.8 - 9.2) associated with the inhalation of cooking fumes [4, 14, 29, 31, 33]. A more detailed investigation of this issue found that use of unrefined Chinese rapeseed oil, compared to soybean oil, was associated with a 1.4-fold increase in risk (95% CI 1.1-1.8) [4]. The excess risk was highest (2.8, 95% CI 1.8-4.3) among women using rapeseed oil who had frequent eye irritation while cooking (a sur rogate marker of relatively high levels of exposure). Another study found that a number of highly muta genic chemicals were emitted when cooking at high temperatures with unrefined rapeseed oil; specifically, 1,3-butadiene, classified as a probable human carcino gen by the International Agency for Research on Cancer [34], had approximately 22-fold higher emis sions when cooking with unrefined rapeseed oil as opposed to peanut oil [13]. This agent has also been detected in cigarette smoke [35]. A study of lung cancer among Chinese women in Singapore observed an odds ratio of 2.8 (95% CI 1.4-5.7) associated with daily stir frying of meat for 20-30 years prior to the date of diagnosis among smokers, but no association in non smokers [15].

There are several other factors that have been exam

ined as potential lung carcinogens, although none could, plausibly, account for all of the excess risk among Chinese women relative to women of other races. Diet, particularly, has been extensively studied, and the excess risk of lung cancer among the lowest consumers of fresh fruits, vegetables, and soy has been found to be between 1.2 and 2.4 [1, 8, 9, 29, 36, 37]. The role of hormonal and reproductive factors has also been examined, with decreased risks of lung cancer of approximately 30-50% seen in non-smoking women with longer menstrual cycles and three or more live births [4, 9].

This content downloaded from �������������130.212.18.96 on Thu, 30 Sep 2021 03:18:27 UTC�������������

All use subject to https://about.jstor.org/terms

Smoking-adjusted lung cancer incidence 1089

o

GO P

O o c 4>

<

IS i 3! o

g a 15 .2 > W)

^ o d? ^

o feb

ce bu X> co

Bu o *

00

a. ?

te 4> O 13 ?t? ti

1 OO

4> 4) > ' ce

CC

co ^_>

^ 2 a> a co 4)

4> Ll ce M"1

O ?*

3 o S co

a1 00

co

S 00

.? 5 'S ^ ? On,

4>

4) Ce Q, 4)

4) ce ce 4) O ce

?

W ce t? -c

T3 4> O Rt 4> ce O. w rr ce W O

T3 4) > Ui 4) ce ce 4? _r> ce

.? On

i> ce

4)

4) ce

4> > 4> ce ce 4)

? le t? -c

73 4) O ?i 4) ce ?V 4)

tLJ u

4> ce ce 4) O ce

rt q vo O? U^ ^

"I ^ *1 VO W ^

On VO "tf ? ~ ?; vf oo */"T o o o

r- ~- on o- o

r^ oo r^ f?-3 i-? ^' r-^ rn irT o o o^ vo r- on ^ ? ?

oo oo m

on Tt ^r ? ?? ?^

vo o r^ ? ~ o

"? rs ro ?, ? ? ON ?Ti (^ ? ? o

p in cn O?

cn ?? ~ ??< ?o m

^ Tf en ?" ? ?

q m vq ?; ^ ?

(^ (N vq cn oo ?

m ?-, *-<

-a s a a .5 c ? i> a co 13 .g

E J5 a ??Ott.

Oh CO a o

' co

The results of our study suggest that, accounting for their level of cigarette smoking, Chinese female residents of the western US mainland have an increased risk of

lung cancer, particularly adenocarcinoma of the lung, just as they do in Asia. From research in Chinese resi dents in Asia, there are clues as to why this might be so, and these could be pursued in cohort and case-control studies in Asian-American women.

References

1. MacLennan R, Da Costa J, Day NE, et al. (1977) Risk factors for lung cancer in Singapore Chinese, a population with high female incidence rates. Int J Cancer 20: 854-860.

2. Chan WC, Colbourne MJ, Fung SC, et al. (1979) Bronchial cancer in Hong Kong 1976-1977. Br J Cancer 39: 182-192.

3. Hinds MW, Stemmermann GN, Yang HY, Kolonel LN, LeeJ., Wegner (1981) Differences in lung cancer risk from smoking among Japanese, Chinese, and Hawaiian women in Hawaii. Int J Cancer 27: 297-302.

4. Gao Y-T, Blot WJ, Zheng W, et al. (1987) Lung cancer among Chinese women. Int J Cancer 40: 604-609.

5. Le Marchand L, Wilkens LR, Kolonel LN (1992) Ethnic differ ences in the lung cancer risk associated with smoking. Cancer Epidemiol Biomarkers Prev 1: 103-107.

6. Koo LC, Ho JH-C, Lee N (1985) An analysis of some risk factors for lung cancer in Hong Kong. Int J Cancer 35: 149-155.

7. Koo LC, Ho JH-C, Saw D, Ho C-y (1987) Measurements of passive smoking and estimates of lung cancer risk among non smoking Chinese females. Int J Cancer 39: 162-169.

8. Zhao B, Seow A, Lee EJD, et al. (2001) Dietary isothiocyanates, glutathione S-transferase -Ml, -Tl polymorphisms and lung can cer risk among Chinese women in Singapore. Cancer Epidemiol Biomarkers Prev 10: 1063-1067.

9. Seow A, Poh W-T, Teh M, et al. (2002) Diet, reproductive factors and lung cancer risk among Chinese women in Singapore: evidence for a protective effect of soy in nonsmokers. Int J Cancer 97: 365 371.

10. LiaoM-L, WangJ-H, WangH-M, OuA-Q, Wang X-J, You W Q (1996) A study of the association between squamous cell car cinoma and adenocarcinoma in the lung, and history of men struation in Shanghai women, China. Lung Cancer 14: S215-S221.

11. Mumford JL, He XZ, Chapman RS, et al. (1987) Lung cancer and indoor air pollution in Xuan Wei, China. Science 235: 217-220.

12. Luo R-X, Wu B, Yi Y-N, Huang Z-W, Lin R-T (1996) Indoor burning coal air pollution and lung cancer - a case-control study in Fuzhou, China. Lung Cancer 14: SI 13?SI 19.

13. Shields PG, Xu GX, Blot WJ, et al. (1995) Mutagens from heated Chinese and U.S. cooking oils. J Nati Cancer Inst 87: 836-841.

14. Wang TJ, Zhou BS, Shi JP (1996) Lung cancer in nonsmoking Chinese women: a case-control study. Lung Cancer 14: S93-98.

15. Seow A, Poh W-T, Teh M, et al (2000) Fumes from meat cooking and lung cancer risk in Chinese women. Cancer Epidemiol Biomarkers Prev 9: 1215-1221.

16. Seow A, Zhao B, Lee EJD, et al. (2001) Cytochrome P4501A2 (CYP1A2) activity and lung cancer risk: a preliminary study among Chinese women in Singapore. Carcinogenesis 22: 673? 677.

17. Surveillance, Epidemiology, and End Results (SEER) Program (www.seer.cancer.gov) SEER*Stat Database: Incidence - SEER 9

This content downloaded from �������������130.212.18.96 on Thu, 30 Sep 2021 03:18:27 UTC�������������

All use subject to https://about.jstor.org/terms

1090 M. Epplein et al.

Regs Public-Use, Nov 2003 Sub (1973-2001), National Cancer Institute, DCCPS, Surveillance Research Program, Cancer Statistics Branch, released April 2004, based on the November 2003 submission.

18. U.S. Census Bureau (2003) Census 2000 Summary File 4 - United States.

19. Burns D, Pierce JP (1992) Tobacco Use in California, 1990-1991, Sacramento: California Department of Health Services.

20. Silcocks P (1994) Estimating confidence limits on a standardised mortality ratio when the expected number is not error free. J Epidemiol Community Health 48: 313-317.

21. Uitenbroek DG (1997 (Accessed 29 July 2004)) SISA-Binomial. http://home.clara.net/sisa/binomial.htm.

22. Fritz A, Percy C, Jack A, Shanmugaratnam K, Sobin L, Parkin DM, Whelan S (eds) (2000) International Classification of Diseases for Oncology, Third Edition, U.S. Interim Version 2000. Geneva: World Health Organization.

23. Centers for Disease Control and Prevention (1992) Cigarette smoking among Chinese, Vietnamese, and Hispanics - California, 1989-1991. MMWR 41: 362-267.

24. Field RW, Smith BJ, Platz CE, et al. (2004) Lung cancer histo logie type in the Surveillance, Epidemiology, and End Results registry versus independent review. / Nati Cancer Inst 96: 1105 1107.

25. Green JP, Brophy P (1982) Carcinoma of the lung in nonsmoking Chinese women. West J Med 136: 291-294.

26. Shimizu H, Wu AH, Koo LC, Gao Y-T, Kolonel LN (1985) Lung cancer in women living in the Pacific Basin area. Nati Cancer Inst Monogr 69: 197-201.

27. Koo LC, Ho JH-C (1990) Worldwide epidemiological patterns of lung cancer in nonsmokers. Int J Epidemiol 19: S14-S23.

28. WangS-Y, Hu Y-L, WuY-L, et al. (1996) A comparative study of risk factors for lung cancer in Guangdong, China. Lung Cancer 14: S99-S105.

29. Dai X-D, Lin C-Y, Sun X-W, Shi Y-B, Lin Y-J (1996) The etiology of lung cancer in nonsmoking females in Harbin, China. Lung Cancer 14: S85-S91.

30. Du Y-X, Cha Q, Chen X-W, et al. (1996) An epidemiological study of risk factors for lung cancer in Guangzhou, China. Lung Cancer 14: S9-S37.

31. Shen X-B, Wang G-X, Huang Y-Z, Xiang L-S, Wang X-H (1996) Analysis and estimates of attributable risk factors for lung cancer in Nanjing, China. Lung Cancer 14: S107-S112.

32. Lei Y-X, Cai W-C, Chen Y-Z, Du Y-X (1996) Some lifestyle factors in human lung cancer: a case-control study of 792 lung cancer cases. Lung Cancer 14: S121-S136.

33. Ko YC, Lee CH, Chen MJ, et al. (1997) Risk factors for primary lung cancer among non-smoking women in Taiwan. Int J Epidemiol 26: 24-31.

34. IARC Working Group on the Evaluation of Carcinogenic Risks to Humans (1992) Occupational exposures to mists and vapours from strong inorganic acids and other industrial chemicals, pp. 54: 51-310. Lyon: IARC.

35. Brunnemann KD, Kagan MR, Cox JE, et al. (1990) Analysis of 1,3-butadiene and other selected gas-phase componenets in ciga rette mainstream and sidestream smoke by gas chromatography

mass selective detention. Carcinogenesis 11: 1863-1868. 36. Koo LC (1988) Dietary habits and lung cancer risk among Chinese

females in Hong Kong who never smoked. Nutr Cancer 11:155-172. 37. Xu Z-Y, Brown L, Pan GW, et al. (1996) Lifestyle, environmental

pollution and lung cancer in cities of Liaoning in northeastern China. Lung Cancer 14: S149-S160.

This content downloaded from �������������130.212.18.96 on Thu, 30 Sep 2021 03:18:27 UTC�������������

All use subject to https://about.jstor.org/terms