Cancer mortality in U.S. counties with petroleum industries.

A survey of cancer mortality from 1950 to 1969 was conducted in U.S. counties where the petroleum industry is most heavily concentrated. Male residents of these counties experienced significantly higher rates for cancers of the lung, the nasal cavity and sinuses, and the skin (including malignant melanoma) compared to male residents of counties with similar demographic characteristics. Further study is needed to determine whether these patterns result from exposure to chemical carcinogens, including polycyclic hydrocarbons, involved in the manufacturing of petroleum.

Geographic patterns of breast cancer in the United States.

To seek explanations for the geographic variation of breast cancer across the continental United States, we calculated the correlations between mortality rates for premenopausal and postmenopausal women and demographic data for the 3,056 U.S. counties. The northern predominance of this tumor was primarily among postmenopausal women, whereas mortality among premenopausal women was distributed almost uniformly across the country. Socioeconomic status (particularly income), German ethnicity, and colon cancer mortality were strong indicators of the rates for postmenopausal women, but only partly explained the northern excess and latitudinal gradient. In contrast, fertility patterns and ovarian cancer mortality were more closely linked to breast cancer among premenopausal women. The geographic peculiarities of this tumor in older women suggest extrinsic risk factors that remain to be identified, whereas the patterns for younger women point to the primary role of reproductive and genetic determinants.

Geographic patterns of large bowel cancer in the United States.

Age-adjusted rates of mortality from colon and rectal cancer during 1950-69 were correlated by sex and race (white and nonwhite) with demographic data for the 3,056 counties of the contiguous United States. Mortality was consistently elevated in counties with large populations, higher income and education levels, and high percentages of residents of Irish, German, or Czechoslovak descent. The urban, socioeconomic, and, ethnic factors were each linked to large bowel cancer, but they only partly explained the predominance of this tumor in the Northern United States. A survey was made of the limited data available on dietary habits by region and on alcohol sales by county, but the concomitant variation with bowel cancer mortality rates was not impressive.

Mortality from multiple myeloma among North Carolina furniture workers.

The risk of multiple myeloma among furniture workers was investigated in a case-control study with the use of death certificate statements on occupation in North Carolina counties with heavy employment in furniture-manufacturing industries. From computerized mortality listings, 301 male deaths from multiple myeloma were identified, and 858 controls were selected from deaths due to other causes; controls were matched by sex, race, county of usual residence, age at death, and year of death. Employment in the furniture industry was associated with a nonsignificant excess risk of multiple myeloma [relative risk (RR) = 1.3], particularly among subjects who died before age 65 (RR = 1.7) and among those born before 1905 (RR = 1.5). A significantly elevated risk (RR = 5.4) was seen for furniture workers who were born before 1905 and died prior to age 65. Unexpectedly, farmers were found to have a significantly decreased risk of multiple myeloma (RR = 0.6). The finding of an elevated risk of myeloma in earlier cohorts of furniture workers may be a clue to the nature of the environmental exposure.

Recent cancer trends in the United States.

BACKGROUND: Cancer incidence rates have been reported to be increasing in the United States, although trends vary according to form of cancer. PURPOSE: We identify the cancers accounting for the rising incidence, quantify the changes that have occurred from the mid-1970s to the early 1990s, and contrast incidence and mortality trends to provide clues to the determinants of the temporal patterns. METHODS: Sex-, race-, and age-specific and age-adjusted incidence rates for the 5-year periods 1987-1991 versus 1975-1979 were calculated for 28 cancers among men and 30 cancers among women using data from the Surveillance, Epidemiology, and End Results (SEER) Program of cancer registration covering about 10% of the U.S. population. Similar rates were computed using national mortality data. Cancers were ranked according to the change in incidence rates over the two periods. RESULTS: Age-adjusted incidence rates for all cancers combined increased by 18.6% among males and 12.4% among females from 1975-1979 to 1987-1991, due largely to rising rates for prostate cancer among men and for breast and lung cancers among women. National mortality rates for all cancers combined rose less steeply, 3% and 6% among men and women, respectively, driven mostly by continuing increases in lung cancer mortality, while death rates for the majority of the cancers were steady or declining. Total cancer incidence rose at all ages, but with different tumors responsible for the increases at different ages: leukemia and brain/nervous system cancer among children; testicular cancer, nonmelanoma skin cancer (largely Kaposi's sarcoma), non-Hodgkin's lymphoma, and melanoma among young and middle-aged adults; and prostate, breast, and lung cancers among older individuals. In contrast, mortality rates for all cancers combined declined among both males and females under age 55 years, increasing only among older persons. CONCLUSIONS: Trends in cancer incidence and mortality differ. For most cancers, incidence rates are rising, while mortality rates are generally stable or declining. IMPLICATIONS: Much of the recent increase in cancer incidence can be explained by known factors. Improved detection appears to account for most of the increases in breast cancer among women and prostate cancer among men. On the other hand, cigarette smoking is the major determinant of the rise in lung cancer among women, acquired immunodeficiency syndrome has led to increases in non-Hodgkin's lymphoma and Kaposi's sarcoma among young and middle-aged men, and sunlight exposure patterns have affected the trends in melanoma. Some trends remain unexplained, however, and may reflect changing exposures to carcinogens yet to be identified and clarified.

Occupational risks for intracranial gliomas in Sweden.

With the use of the Cancer-Environment Registry, which links cancer incidence for the years 1961-79 with 1960 census information on occupation for all employed individuals in Sweden, a systematic population-based assessment according to employment classifications was made of the occurrence of intracranial gliomas. Statistically significant (P less than .05) increases in the incidence of intracranial gliomas were observed among several professional and white-collar occupations, possibly due in part to higher levels of diagnosis and reporting of this particular neoplasm. Significantly elevated rates were noted among male dentists, agricultural research workers, and public prosecutors and among female physicians and employees in the health care industry. For blue-collar workers, significant excesses were found among welders and metal cutters; glass, porcelain, or ceramic workers; cellulose plant employees; brick and tile workers; and women employed in the wool industry. Several findings of this survey may represent new clues to the etiology of intracranial gliomas, while other findings support observations reported in previous studies.

Leukemia after therapy with alkylating agents for childhood cancer.

The risk of leukemia was evaluated in 9,170 2-or-more-year survivors of childhood cancer in the 13 institutions of the Late Effects Study Group. Secondary leukemia occurred in 22 nonreferred individuals compared to 1.52 expected, based on general population rates [relative risk (RR) = 14; 95% confidence interval (CI), 9-22]. The influence of therapy for the first cancer on subsequent leukemia risk was determined by a case-control study conducted on 25 cases and 90 matched controls. Treatment with alkylating agents was associated with a significantly elevated risk of leukemia (RR = 4.8; 95% CI, 1.2-18.9). A strong dose-response relationship was also observed between leukemia risk and total dose of alkylating agents, estimated by an alkylator score. The RR of leukemia reached 23 in the highest dose category. Radiation therapy, however, did not increase risk. Although doxorubicin was also identified as a possible risk factor, the excess risk of leukemia following treatment for childhood cancer appears almost entirely due to alkylating agents.

Indoor radon and lung cancer in China.

Radon has long been known to contribute to risk of lung cancer, especially in undergound miners who are exposed to large amounts of the carcinogen. Recently, however, lower amounts of radon present in living areas have been suggested as an important cause of lung cancer. In an effort to clarify the relationship of low amounts of radon with lung cancer risk, we placed alpha-track radon detectors in the homes of 308 women with newly diagnosed lung cancer and 356 randomly selected female control subjects of similar age. Measurements were taken after 1 year. All study participants were part of the general population of Shenyang, People's Republic of China, an industrial city in the northeast part of the country that has one of the world's highest rates of lung cancer in women. The median time of residence in the homes was 24 years. The median household radon level was 2.3 pCi/L of air; 20% of the levels were greater than 4 pCi/L. Radon levels tended to be higher in single-story houses or on the first floor of multiple-story dwellings, and they were also higher in houses with increased levels of indoor air pollution from coal-burning stoves. However, the levels were not higher in homes of women who developed lung cancer than in homes of controls, nor did lung cancer risk increase with increasing radon level. No association between radon and lung cancer was observed regardless of cigarette-smoking status, except for a nonsignificant trend among heavy smokers. No positive associations of lung cancer cell type with radon were observed, except for a nonsignificant excess risk of small cell cancers among the more heavily exposed residents. Our data suggest that projections from surveys of miners exposed to high radon levels may have overestimated the overall risks of lung cancer associated with levels typically seen in homes in this Chinese city. However, further studies in other population groups are needed to clarify the carcinogenic potential of indoor radon.

Occupational risks for pleural mesothelioma in Sweden, 1961-79.

From national population-based registries linking cancer incidence from 1961 to 1979 with 1960 census data on industry and occupation for all employed individuals in Sweden, a systematic assessment was made of pleural mesothelioma occurrence according to occupational and industrial classifications. There were 318 cases of pleural mesothelioma recorded during the 19-year follow-up period among males employed in 1960, with significant variation by industrial and occupational categorizations. The observed number of pleural mesotheliomas for men employed in the sugar refining, cellulose, wood and pulp, shipbuilding, and railroad equipment manufacturing industries was more than three times the number expected. Occupations with at least twofold excess of mesotheliomas included the craftsman categories of plumbers, mechanics and repairmen, electricians, painters, tire makers, and stationary equipment operators. Our findings are consistent with available data relating mesothelioma to occupational asbestos exposure in other countries, although unexpected associations were found that deserve further epidemiologic study.

Smoking, air pollution, and the high rates of lung cancer in Shenyang, China.

A case-control study involving interviews with 1,249 patients with lung cancer and 1,345 population-based controls was conducted in Shenyang, an industrial city in northeastern China, where mortality rates are high among men and women. Cigarette smoking was found to be the principal cause of lung cancer in this population, accounting for 55% of the lung cancers in males and 37% in females. The attributable risk percentage among females is high compared to elsewhere in China, largely because of a higher prevalence of smoking among women. After adjustment for smoking, there were also significant increases in lung cancer risk associated with several measures of exposure to air pollutants. Risks were twice as high among those who reported smoky outdoor environments, and increased in proportion to years of sleeping on beds heated by coal-burning stoves (kang), and to an overall index of indoor air pollution. Threefold increases in lung cancer risk were found among men who worked in the nonferrous smelting industry, where heavy exposures to inorganic arsenic have been reported. The associations with both smoking and indoor air pollution were stronger for squamous cell and small cell carcinomas than for adenocarcinoma of the lung. Risks due to smoking or air pollution were not greatly altered by adjustment for consumption of fresh vegetables or sources of beta carotene or retinol, prior chronic lung diseases, or education level. The findings suggest that smoking and environmental pollution combine to account for the elevated rates of lung cancer mortality in Shenyang.

A death certificate analysis of nasal cancer among furniture workers in North Carolina.

A case-control study of nasal cancer, based on death certificate statements on occupation in North Carolina counties with furniture-manufacturing industries, revealed a 4-fold excess risk linked to this occupation. Although woodworking exposures have been associated with nasal adenocarcinomas in several areas of the world, this is the first report of such a relationship in the United States.

Registry-based analysis of occupational risks for primary liver cancer in Sweden.

A systematic evaluation was made of the occurrence of microscopically confirmed primary liver cancer (International Classification of Disease, 7th Rev., 155.0) among men by industrial and occupational classification using the Cancer-Environment Registry, which links cancer incidence (1961-1979) and census data (1960) on industry and occupation for all employed persons in Sweden. A number of blue collar jobs were found to be significantly associated with primary liver cancer, including men employed in breweries, slaughterhouses, grain mills, shoe fabrication, basic industrial chemicals, plumbing and pipefitting, and insulation work. Although brewery workers and several white collar and service employment categories had significantly increased risks, the influence of alcohol intake was suggested by a parallel mortality analysis showing that most categories had excesses of liver cirrhosis and alcoholism. While often consistent with previous studies, the findings of this registry-based survey should be considered primarily as hypothesis generating in nature.

Occupational risks for bladder cancer among men in Sweden.

With the use of the Swedish Cancer-Environment Registry, census data on employment in 1960 were linked with registry data on bladder cancer during 1961-79. This hypothesis-generating study revealed for the first time associations between bladder cancer and employment in pulp and fiberboard manufacturing, in rope and twine making, and work as a dental technician. Statistically significant increases in risk were also found for several occupations previously associated with bladder cancer, including barbers and beauticians, artistic painters, toolmakers and machinists, and physicians, and employment in butcher shops, industrial chemical making, apparel manufacturing, and plumbing. Etiologic inferences cannot be made from this investigation, but the findings from this large national resource provide further clues to the occupational determinants of bladder cancer.

Therapeutic radiation at a young age is linked to secondary thyroid cancer. The Late Effects Study Group.

We estimated the risk of thyroid cancer among 9170 patients who had survived 2 or more years after the diagnosis of a cancer in childhood. As compared with the general population, patients had a 53-fold increased risk (95% confidence interval, 34-80). Risk increased significantly with time since treatment for the initial cancer (P = 0.03). Detailed treatment data were obtained for 23 cases and 89 matched controls from the childhood cancer cohort. Sixty-eight % of the thyroid cancers arose within the field of radiation. Radiation doses to the thyroid of greater than 200 cGy were associated with a 13-fold increased risk (95% confidence interval, 1.7-104). The risk of thyroid cancer rose with increasing dose (P less than 0.001), but this was derived almost entirely from the increase from less than 200 to greater than 200 cGy. The risk of thyroid cancer did not decrease, however, at radiation doses as high as 6000 cGy.

CYP1A1 and GSTM1 polymorphisms in relation to lung cancer risk in Chinese women.

We examined CYP1A1 (I462V) and GSTM1 null polymorphisms in 200 female cases and 144 female controls selected from a population-based case-control study of lung cancer conducted in northeast China, where the rates of lung cancer among Chinese women are especially high. The CYP1A1 codon 462 point mutation in exon 7 (I462V) causes an Ile-Val substitution near the heme binding site. This mutation correlates with inducibility of aryl hydrocarbon hydrolase (AHH) activity, which activates polycyclic aromatic hydrocarbons (PAHs) in tobacco smoke and in indoor air pollution from coal-burning stoves, a risk factor for lung cancer in this study population. We found that the CYP1A1 I462V genotype (combined ile/val and val/val) was significantly associated with lung cancer risk. The odds ratio (OR) was 2.5 (95% confidence interval [CI], 1.55-4.03) after adjustment for significant risk factors such as age, ever smoking status, family history of cancer, and eye irritation when cooking. The association was more pronounced among non-smokers (OR=3.67; 95% CI, 1.85-7.28) than among smokers (OR=1.74, 95% CI, 0.85-3.54). In contrast, we did not find a significant association with the GSTM1 null genotype. In summary, our case-control study of lung cancer among women in northeast China revealed an elevated risk associated with the CYP1A1 I462V genotype, but no interaction with smoking or indoor air pollution was found.

Correlates of liver cancer mortality in China.

To provide clues to the causes of liver cancer in China, we studied the correlation of certain dietary and biochemical markers with liver cancer mortality across 65 Chinese counties. Mortality rates were significantly linked to the county-wide prevalence of hepatitis-B surface antigen positivity. Rates were also higher in counties with high plasma levels of total cholesterol and high consumption of liquor, rapeseed oil, and mouldy corn, while inverse associations were observed for wheat consumption. All of the observed associations, except those with cholesterol and rapeseed oil, were more pronounced in men than in women. No significant correlations with liver cancer mortality were found for consumption of several other foods; plasma levels of retinol, beta-carotene, alpha-tocopherol, selenium, zinc and ferritin; or urine levels of aflatoxin B1. Although causal inferences cannot be derived, this ecological study suggests that chronic infection with hepatitis-B virus contributes to the substantial variation in liver cancer mortality in China, and provides leads for further studies into the role of dietary and nutritional determinants.

The incidence of regurgitation during cardiopulmonary resuscitation: a comparison between the bag valve mask and laryngeal mask airway.

The risk of gastric regurgitation and subsequent pulmonary aspiration is a recognised complication of cardiac arrest--a risk which may be further increased by the resuscitative procedure itself. The purpose of this study was to compare the incidence of gastric regurgitation between the bag valve mask (BVM) and laryngeal mask airway (LMA). The resuscitation data collection forms of 996 patients who underwent in-hospital cardiopulmonary resuscitation over a 3.5 year period were reviewed. Of these, 199 patients were excluded from the study because there was no airway management involving a BVM or LMA. The incidence and timing of regurgitation was studied in the remaining 797 patients. Regurgitation was recorded to have occurred at some stage in 180 of these patients (22.6%). However, 84 regurgitated prior to CPR (46.7% of those patients who regurgitated). These patients were excluded from further analysis as regurgitation could not have been affected by any form of ventilation. Of the remaining 713 patients, BVM ventilation was used in 636 cases. In 170 of these the LMA was also used following the BVM. Where the patient was ventilated with the BVM alone or BVM followed by ETT the incidence of regurgitation during CPR was 12.4%. The LMA was used during resuscitation in 256 cases of which 170 had BVM ventilation prior to the LMA. Where the patient was ventilated with the LMA alone or LMA followed by ETT the incidence of regurgitation during CPR was 3.5%. The study confirms experience reported in earlier studies that when an LMA is used as a first line airway device, regurgitation is relatively uncommon.

Occupational risks for cutaneous melanoma among men in Sweden.

A population-based linked-registry was used to evaluate incidence of malignant melanoma of the skin among Swedish men by industry and occupation. There were 3850 cutaneous melanoma cases identified in the 19-year follow-up of men employed in 1960. New associations were observed for men employed in the breweries and malt-processing industry and in shoe fabrication from leather and skins. Several findings supported associations previously reported in other countries, including an excess risk among workers in basic chemical production and the printing industry and among professional, technical, and white-collar workers. Risk overall was not increased among farmers, despite a significant excess of melanoma of the face, neck, and scalp. Although this linked registry analysis lacked information about specific agents, duration of employment, and occupational and recreational sun exposures, it did provide leads for new associations and confirmed previous ones. Nevertheless, because of these limitations, etiologic clues must be interpreted cautiously.

Occupation and prostate cancer risk in Sweden.

To provide new leads regarding occupational prostate cancer risk factors, we linked 36,269 prostate cancer cases reported to the Swedish National Cancer Registry during 1961 to 1979 with employment information from the 1960 National Census. Standardized incidence ratios for prostate cancer, within major (1-digit), general (2-digit), and specific (3-digit) industries and occupations, were calculated. Significant excess risks were seen for agriculture-related industries, soap and perfume manufacture, and leather processing industries. Significantly elevated standardized incidence ratios were also seen for the following occupations: farmers, leather workers, and white-collar occupations. Our results suggest that farmers; certain occupations and industries with exposures to cadmium, herbicides, and fertilizers; and men with low occupational physical activity levels have elevated prostate cancer risks. Further research is needed to confirm these findings and identify specific exposures related to excess risk in these occupations and industries.

Multiple myeloma and occupation in Sweden.

The occurrence of multiple myeloma by occupational and industrial category was systematically assessed using the Swedish Cancer-Environment Registry, which links cancer incidence (1961-1979) with occupational data from the 1960 census. Incidence of multiple myeloma was significantly increased for a number of occupational groups such as farmers, smelter and metallurgy workers, and miners-quarrymen-rock blasters. Although caution must be applied in drawing causal inferences, this national linked-registry analysis may provide clues to the environmental determinants of multiple myeloma.