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 , I I I I I I I I I I 5. Diet. Food categories analyzed included: pork, beef, poultry, fish, egg and dairy products, leafy and nonleafy vegetables, fruits, fried food, preserved vegetables, salt-preserved fish and smoked and cured foods. The results show that the consumption of fresh vegetables and fruits have protective properties against lung cancer in males. On the other hand, fried food may contribute to the risk of lung cancer in males. No differences were shown for the remainder of the food categories. (Table 5) When data were stratified into "never" or "frequent" (almost daily) intake groups for comparison, then the correlations between frequent intake of vegetables and fruit and the decrease of male lung cancer rate became more pronounced. (Tables 6, 7) N 0 ~ 1 °° V 00 W ~ -7- C~Ir i ,

(B) Analysis of compatibility: The demographic characteristics obtained on cases and controls were first subjected to the X1 Test to ascertain compatibility. These include father's place of birth (Guangzhou or other); marital status (single, married, divorced, widowed, separated); education (illiterate, primary school, middle school, high school, technical school, or college education); occupation (professional, government official, clerk, businessman, service personnel, manual laborer, and others). (C) Stratification and analysis of factors: For bipartite variables the X2 value was calculated by the McNemar method. The odds ratio (OR) with a 95% CI were determined according to Miettinen. To obtain information on total exposure; the cumulative X2 was calculated by the RXC table for pooled theoretical value method and OR were calculated. 1. Quality of survey data. Results and Analysis Data from 272 samples, i.e. 8 pairs of cases and controls and 17 risk factors were taken by investigators A and B. As shown in Table 1 the data were accurate and reliable. Table 1. 272 Samples of Risk Factors Taken By Investigators A & B Investigator B Investigator A Yes No Total Yes 99 15 114 No 10 148 158 Total 109 163 272 Result of Kappa Test: K = 0.81, P < 0.001 2. Test of Balance. Uniformity exists for cases and the controls in sex, age of death, and street address. The distribution of the other demographic characteristics of the cases and the controls include father's place of birth, marital status, education, and occupation which was also distributed uniformly. No difference was found by the test of balance, which demonstrated good compatibility between the two groups (Table 2). -4- I I I 1 I I I I I I I I I I I I

I I I 46. I 47. I I I I I I I I I I I Wang, X.Z. et al. "Experiments of mutagenicity in indoor and outdoor pollutants," Second Chinese Conference on Environmental Health, Nanjing, 1984. Abstracts. Ou, Z.L. eta l. "Relationship of coal-burning and lung cancer in housewives," Proceedings of Second Conference of Cancer Research, Guangzhou, 1987, p. 76-81. 0 , tb i V 0 -19- W N w ,

I I I I I I I I I I I I I I I I Table 2. Demographic Characteristics of Cases and Controls Male Female Cates Conttols Cases Controls Native province Guangdong Provlnce 465 454 179 182 Province other than Guangdong 32 43 12 9 X2 =1.745 P>0.05 X2 =0.213 P>0.05 Marital status Single 13 22 8 6 Married 476 473 147 139 Divnrced 14 8 1 4 Widowed 28 34 64 67 Separated 12 6 3 7 x2 =6.541 P>0.05 g2=2.158 P>0.05 Bducation Illiterve 47 44 100 107 Grade School 264 249 80 69 Middle Schoul 131 124 23 26 High School & Technical 66 81 15 16 College 36 46 4 4 x2=3.480 P > 0.05 X2 =1.258 P>0.05 Occupxtion Profasional 49 50 19 9 Government official 46 48 2 2 Clerical 32 46 4 4 Other 35 49 38 46 Business 41 56 12 13 Service Personnel 48 40 21 19 Laborer 270 232 75 78 x2 = 10.822 P> 0.05 2 = 4.532 P> 0.05 3. Analysis of smoking history. Among the 563 pairs of male cases and controls, the percentage of smokers was 92.5 % for the cases and 75.5% for the controls. Among the 229 female pairs, the smoking rate was 60.6% for the cases and 30.8% for the controls. The majority of smokers smoked cigarettes (68.2%); the next largest smoker group used roll-your-own cigarettes (28.3%); a few used water pipes (1.9%); and a very small number used pipes and cigars. Though little difference existed in the type of tobacco product used, both the male and the female cases had significantly higher smoking indexes and the test of trend also revealed an obvious dose-response relationship. (Table 3) These results support the view that smoking is an important risk factor in the incidence of lung cancer among residents of Guangzhou. N O -4 , O -4 O W , -5 A tG I

I I I I I I I I I I I I I I SOME LIFESTYLE FACTORS IN HUMAN LUNG CANCER: A CASE-CONTROL STUDY OF 792 LUNG CANCER CASES Lei Yi-xiong, Chen Yong-zhong and Du Ying-xiu Department of Hygiene, Guangzhou Medical College, Guangzhou, China Abstract Eating habits and living conditions are fundamental lifestyle factors. Likewise, cigarette smoking, exposure to environmental tobacco smoke (ETS) and other indoor air pollutants are also commonly encountered in many societies. Many studies have examined the possible effects of these factors on the incidence of lung cancer and often produce different and at times conflicting results and conclusions. In order to investigate a relationship between some lifestyle factors and lung cancer, a case-control study involving all lung cancer deaths registered in 1986 was performed. The results show that among males, 92% of the cases and 76% of controls were smokers, implying that cigarette smoking is a primary risk factor for lung cancer in males. By contrast, among females only 60% of the cases and 30% of the controls were smokers, implying factors other than cigarette smoking must be involved in the development of lung cancer in females. As for the exposure to ETS, our results show that the risk of lung cancer in nonsmoking females was not increased by exposure to ETS. The studies of diet and eating habits show that the intake of vegetables and fruits could reduce the risk of lung cancer in males. Similar results have been reported elsewhere. Our studies also show that in the case of males the incidence of lung cancer was significantly increased in those that have a frequent intake of fried food. The positive association established from the studies between the intake of fried food and the risk of lung cancer could result from cooking practices and from inappropriate methods used in food preparation. With regard to the question of high protein diets, high fat diets, salty food and smoked food and their relationship to lung cancer incidence, different results have been observed. Our results show that no association can be demonstrated between the intake of foods mentioned and the incidence of lung cancer. Thus, it is not likely that lung cancer inducing carcinogens can be generated through the intake of food. ~ In addition, the positive association found to exist between the living index and the risk of lung cancer in females indirectly points to coal smoke or cooking practices generating indoor air pollutants and thereby contributing to a risk of lung cancer in females. However, many chemical carcinogens such as . B(a)P are known to be inducers for squamous cell carcinoma of the lungs, but in the case of females, , adenocarcinoma is found to be the predominant cell type. Therefore, the effect of lung air pollution on the incidence of lung cancer needs to be further investigated. ~ ~ 00 i V Do W ~ 1 A I

Table 3. Distribution of Smoking Index in Cases and Controls Smoking Index Cases Controls OR 95% CI Tests M: 0 41 123 1.00 1.00-1.00 Test of hypothesis < 400 57 93 1.84 1.24-3.26 X2 = 77.71, P< 0.001 400-799 136 122 3.34 2.72-5.60 Test of Trend > 800 250 146 5.36 3.60-7.93 X2 = 77.33, P< 0.001 F: 0 85 147 1.00 1.00-1.00 Test of hypothesis < 400 29 26 1.93 1.70-3.02 X2 = 44.68, P< 0.001 400-799 33 16 3.57 2.45-5.11 Test of Trend > 800 61 19 5.55 3.21-7.22 X2 = 43.92, P< 0.001 Note: Smoking index = daily smoking rate times total years of smoking. 4. Passive smoking. To determine the effects of the husbands' smoking on their wives, the following factors were taken into consideration: spousal smoking, daily smoking rate, and years of smoking. These factors were examined to evaluate the effects of exposure to husbands' smoking on nonsmoking wives which are compared in both case and control groups in Table 4. The results did not show a significant relationship between the husbands' smoking status, or the daily number of cigarettes smoked, or the number of years of smoking and the occurrence of lung cancer in their wives. Table 4. Distribution of ETS Exposure Among Nonsmoking Cases and Controls Cases Controls OR 95% Confidence Level ETS exposure No 28 53 Yes 47 75 1.19 0.66-2.16 X2 =0.327 P> 0.05 Amount of exposure to ETS 0 28 53 1.00 1.00-1.00 (number of cigarettes) < 20 13 34 0.72 0.53-0.98 > 20 30 35 1.62 1.03-2.55 X2 = 4.308 P > 0.05 Length of exposure to ETS 0 28 53 1.00 1.00-1.00 (years) < 30 14 19 1.39 0.63-1.60 > 30 29 47 1.17 0.80-1.25 X2 = 0.652 P > 0.05 -6- I I I I I I I I I I I I

I I I I I I I I I I I I I I I I I I (A) Smoking history: Specifically, daily smoking rate (cigarette/day), age at which the person began to smoke, years of smoking, and smoking index (daily smoking rate times years of smoking). The smoking index was divided into four categories: 0, <400, 400-799, >800. In our analysis, we used the smoking index to compare the effects of smoking on the cases and the controls. (B) Exposure to ETS: In order to assess the effects of exposure to environmental tobacco smoke (ETS), the effect of active smoking must be first excluded. Since 92% of the male lung cancer cases were active smokers and since the workplace exposure to ETS cannot be accurately determined, the present survey concerned itself only with the effects of exposure to spousal smoking in non-smoking females. The daily cigarette smoking rate and the years of smoking by the husbands were used in the statistical analysis. (C) Diet history: Survey items included the consumption of pork, beef, poultry, fish, eggs, milk and dairy products, leafy and nonleafy vegetables, fruits, fried food, pickled vegetables, salted fish and smoked and cured foods. The consumption of these food items was stratified into the categories of: never, weekly, and daily. (D) Living conditions: Data concerning the following were obtained: old or new building; location of residence within the building (ground level, second, third, or fourth floor and above); interior dimensions including ceiling height (6, 9 or 12 feet) and average size of living area per person (18, 36, 54, 72 square feet per person); ventilation (excellent: 1; medium: 2; poor: 3); and use of insect repelling incense (never, occasional, average, and frequent). (E) Kitchen facilities and exposure to coal smoke/dust: Information obtained included average kitchen size (< 9, 9-18, > 18 square feet) and the type of cooking fuel used (coal, propane, wood). Information was also obtained regarding exposure to benzo(a)pyrene as pollutants generated by frying food, and the preference for cooking by frying. 4. Methods of analysis. (A) Quantitative data analysis. To estimate the reliability of the information collected, 1% of the total sample was randomly resurveyed. Consistency of data between the first and second survey measurements was evaluated by the Kappa test using the following equation. Po-Pe K = where 1 -Pe Po = consistency of observation agree. Pe = the value expected based on consistency obtained solely by chance. The significance of the Kappa test was evaluated by the Fleis 3-level assessment: 0.75..,1.00 excellent p co concordance 4 A 0 75 avera e concordance 0 01 A 3 l ki d ; . . g ; . .. . ac ng concor ance. i -4 CO W 3- A V I

Table 8. Distribution of Living Conditions of Cases and Controls Male Female No. % No. % No. % No. % of Cases of Controls of Cases of Controls Home New building 255 47.1 248 45.8 91 41.7 83 38.1 characteristics Old building 286 52.9 ~ 293 54.2 127 58.3 135 61.9 XT---7-0-182 P> 0.05 Xrt-::--0.612 P> 0.05 Floor within the Istfloor 220 45.4 211 43.5 78 42.6 88 48.1 building 2nd floor 129 26.6 132 27.2 51 27.9 50 27.3 3rd floor 64 13.2 68 14.0 29 15.8 27 14.8 4th floor and 72 14.8 74 15.3 25 13.7 18 9.8 above XT-=-0.371 P> 0.05 X-=-1.823 _P> 0.05 Ceiling height 2 or more 35 7.1 23 4.7 9 4.3 17 8.2 (M) 3 or more 302 61.3 310 62.9 119 57.2 107 51.4 4 or more 156 31.6 160 32.5 80 38.5 84 40.4 X2-=-2 638 P> 0.05 XT-=-3 196 P> 0.05 Living space 2 or more 165 30.3 137 25.1 58 26.5 66 30.1 (M2lperson) 4 or mom 122 22.4 132 24.3 59 26.9 50 22.8 6 or more 97 17.8 103 18.9 34 15.5 37 17.0 8 or more 160 29.4 172 31.6 68 31.1 66 31.1 XT 3.603 P> 0.05 XX = 1.416 P> 0.05 Room ventilation Good (I) 226 41.1 228 41.5 73 33.8 77 35.6 Medium (2) 208 37.8 230 41.8 93 43.1 87 40.3 Poor(3) 116 21.1 92 16.7 50 23.1 52 24.1 X2---3 883 P> 0.05 X7 = 0.346 P> 0.05 Burning of insect Never 193 34.9 205 37.0 97 43.9 75 33.9 repellant incense Occasional 168 30.4 150 27.1 57 25.8 72 32.6 Average 100 18.1 108 19.5 35 15.8 42 19.0 Frequent 92 16.6 91 16.4 32 14.5 32 14.5 XZ = 1.693 P> 0.05 XT= 5.195 P> 0.05 -10- i I I I I I I I I I I I

I I I I I I I I I I 1 I I ~ I I I I Table 6. Analysis of Fresh Vegetable Intake by Male Cases and Controls Cases Controls Not Regularly Regularly Total Not regularly 0 8 8 Regularly 30 518 548 Total 30 526 556 OR = 3.75 95 % CI 1.75-8.00 X2 = 11.605 P < 0.001 Table 7. Analysis of Fruit Intake by Male Cases and Controls Frequency Cases Controls Total Not regularly Regularly 78 125 92 250 170 375 Total 203 342 545 OR 1.36 95 % CI 1.04-1,78 X2 = 5.018 P < 0.05 6. Conditions of living quarters. To describe the characteristics of living quarter conditions, the following data were collected: building characteristics, floor within the building, ceiling height, average living space per person, room ventilation, frequency of burning of insect repellant incense. The results showed no obvious differences between the case and the control groups. (Table 8) However, when the living conditions index, i.e. average living area per person (M2/number of persons)/room ventilation (1, 2, 3), was used for a combined evaluation, it was found to be related to female lung cancer (Table 9), i.e., when the living conditions index was low the female lung cancer rate showed an upward trend. N O tb -L V -9- w N Cn W I

I I I I I I I I I I I I I I I I I 1 Table 9. Analysis of Living Conditions Index Male Female Living Condition Index Cases Controls OR 95% CI Cases Controls OR 95% CI 8 or more 100 104 1.00 1.00-1.00 25 46 1.00 1.00-1.00 4 or more 126 112 1.17 0.89-1.54 64 46 2.56 1.394.70 1 or more 288 304 0.99 0.97-1.01 111 108 1.89 1.25-2.85 Male: X2 = 1.276 P > 0.05 Female: X2 = 9.199 P < 0.05 7. Kitchen facilities and exposure to coal fume and dust. For residents of Guangzhou, wood was the main fuel source in the 1950s. Coal began to be used as a fuel in the 1960s, and its usage has increased since that time. Beginning in the 1980s individual families began to use propane gas. The investigation of kitchen facilities, coal fumes and dust exposure in the current study showed the following: 91.9% of the families used coal as the major source of fuel during the past 20 years (with 46.2 % of them using wood simultaneously); only 4.6 % used propane and 3.5 % used other fuels. There was no significant difference between the cases and controls with respect to the type of fuel used. Although there was an apparent difference in the cooking activities between the male and female groups (37% of males and 86% of females regularly participated in cooking), no obvious difference was detected between cases and controls within each sex group. Neither was any appreciable differences found between the cases and the controls with regard to kitchen space, years of regular cooking activity, exposure to coal smoke/dust and whether frying was generally the preferred style of cooking. (Table 10) N 0 00 , V tb W -11- N UT I