Proton pump inhibitors and risk of gastric cancer: a population-based cohort study.

Proton pump inhibitor (PPI) use leads to hypergastrinaemia, which has been associated with gastrointestinal neoplasia. We evaluated the association between PPI use and risk of gastric cancer using population-based health-care registers in North Jutland, Denmark, during 1990-2003. We compared incidence rates among new users of PPI (n=18,790) or histamine-2-antagonists (H2RAs) (n=17,478) and non-users of either drug. Poisson regression analysis was used to estimate incidence rate ratios (IRRs) adjusted for multiple confounders. We incorporated a 1-year lag time to address potential reverse causation. We identified 109 gastric cancer cases among PPI users and 52 cases among H2RA users. After incorporating the 1-year lag time, we observed IRRs for gastric cancer of 1.2 (95% CI: 0.8-2.0) among PPI users and 1.2 (95% CI: 0.8-1.8) among H2RA users compared with non-users. These estimates are in contrast to significant overall IRRs of 9.0 and 2.8, respectively, without the lag time. In lag time analyses, increased IRRs were observed among PPI users with the largest number of prescriptions or the longest follow-up compared with H2RA users or non-users. Although our results point to a major influence of reverse causation and confounding by indication on the association between PPI use and gastric cancer incidence, the finding of increased incidence among PPI users with most prescriptions and longest follow-up warrants further investigation.

Dietary vitamin D and cancers of the oral cavity and esophagus.

BACKGROUND: Data on the association between vitamin D and upper digestive tract neoplasms are limited. METHODS: In two case-control studies in Italy, we examined the relation between dietary vitamin D intake and squamous cell carcinoma of the esophagus (SCCE; 304 cases) and oral/pharyngeal cancer (804 cases). Odds ratios (ORs) and 95% confidence intervals (CIs) were estimated by multiple logistic regression. RESULTS: Adjusted ORs for SCCE and oral/pharyngeal cancer were 0.58 (95% CI 0.39-0.86) and 0.76 (95% CI 0.60-0.94), respectively, for the highest tertile of vitamin D intake. Using a reference group of those in the highest tertile of vitamin D who were never/former smokers, ORs were 8.7 (95% CI 4.1-18.7) for SCCE and 10.4 (95% CI 6.9-15.5) for oral/pharyngeal cancer among heavy smokers in the lowest vitamin D tertile; similarly, compared with those in the highest tertile of vitamin D who drank <3 alcoholic drinks/day, corresponding ORs were 41.9 (95% CI 13.7-128.6) for SCCE and 8.5 (95% CI 5.7-12.5) for oral/pharyngeal cancer, among heavy alcohol drinkers in the lowest vitamin D tertile. CONCLUSION: We observed inverse associations between dietary vitamin D intake and risk of SCCE and, perhaps, oral/pharyngeal cancer, which were most pronounced among heavy current smokers and heavy consumers of alcohol.

Vitamin D intake and breast cancer risk: a case-control study in Italy.

BACKGROUND: Vitamin D has been suggested to play a protective role against several cancers, including breast cancer. PATIENTS AND METHODS: We used data from a case-control study conducted in Italy from 1991 to 1994 to study the relation between dietary intake of vitamin D and breast cancer risk. Subjects were 2569 women with incident, histologically confirmed breast cancer and 2588 hospital controls. Odds ratios (ORs) and 95% confidence intervals (CIs) according to deciles of vitamin D intake were estimated by multiple logistic regression models. RESULTS: After allowance for major risk factors for breast cancer and dietary covariates including calcium and energy intake, there was no association with vitamin D up to the seventh decile. Thereafter, the OR declined, so that the overall trend was statistically significantly inverse. The OR for subjects in the three highest deciles of consumption compared with those in the lowest ones combined was 0.79 (95% CI 0.70-0.90). Intake of vitamin D >3.57 microg or 143 IU appeared to have a protective effect against breast cancer. The inverse association was consistent across strata of menopausal status. CONCLUSIONS: This study adds to the existing evidence that vitamin D intake in inversely associated with breast cancer risk.

Dietary glycemic load and hepatocellular carcinoma with or without chronic hepatitis infection.

BACKGROUND: Hepatitis B virus (HBV) and hepatitis C virus (HCV) are the major risk factors for hepatocellular carcinoma (HCC). The association of diabetes mellitus with HCC suggests that dietary glycemic load (GL) may influence HCC risk. We have examined the association between dietary GL and HCC. PATIENTS AND METHODS: We conducted a hospital-based case-control study in Italy in 1999-2002, including 185 HCC cases and 412 controls who answered a validated food frequency questionnaire and provided blood samples. Odds ratios (ORs) and corresponding 95% confidence intervals (CIs) were computed using unconditional multiple logistic regression. RESULTS: We observed a positive association between GL and HCC overall, with an OR of 3.02 (95% CI 1.49-6.12) for the highest quintile of GL compared with the lowest and a significant trend. The OR among HCC cases with evidence of chronic infection with HBV and/or HCV was 3.25 (95% CI 1.46-7.22), while the OR among those with no evidence of infection was 2.45 (95% CI 0.69-8.64), with no significant trend. The association was not explained by the presence of cirrhosis or diabetes. CONCLUSIONS: High dietary GL is associated with increased risk for HCC. The positive association was most pronounced among HCC cases with HBV and/or HCV markers.

Formaldehyde and cancer risk: a quantitative review of cohort studies through 2006.

BACKGROUND: Occupational exposure to formaldehyde has been associated with excess risk of nasopharyngeal and selected other cancers. PATIENTS AND METHODS: We reviewed and pooled the results of cohort studies published through February 2007. RESULTS: There were 5651 deaths from all cancers observed in six cohorts of industry workers and six of professionals, with a pooled relative risk (RR) of 0.95 for industry workers and of 0.87 for professionals. Nine deaths from nasopharyngeal cancer in three cohorts of industry workers yielded a pooled RR of 1.33, which declined to 0.49 after excluding six cases from one US plant. The pooled RR for lung cancer was 1.06 in industry workers and 0.63 in professionals. Corresponding values were 1.09 and 0.96 for oral and pharyngeal, 0.92 and 1.56 for brain, 0.85 and 1.31 for all lymphatic and hematopoietic cancers, and 0.90 and 1.39 for leukemia. CONCLUSIONS: Comprehensive review of cancer in industry workers and professionals exposed to formaldehyde shows no appreciable excess risk for oral and pharyngeal, sinonasal or lung cancers. A non-significantly increased RR for nasopharyngeal cancer among industry workers is attributable to a cluster of deaths in a single plant. For brain cancer and lymphohematopoietic neoplasms there were modestly elevated risks in professionals, but not industry workers.

Outcome of peptic ulcer bleeding among users of traditional non-steroidal anti-inflammatory drugs and selective cyclo-oxygenase-2 inhibitors.

BACKGROUND: Few data exist on the impact of non-steroidal anti-inflammatory drug use on peptic ulcer outcome. AIM: To examine the 30-day mortality from peptic ulcer bleeding associated with the use of traditional non-steroidal anti-inflammatory drugs and newer selective cyclo-oxygenase-2 inhibitors. METHODS: Cohort study of patients with a first hospitalization for peptic ulcer bleeding in three Danish counties between 1991 and 2003. Data on pre-admission non-steroidal anti-inflammatory drug use, use of other ulcer-related drugs and comorbidities were obtained from population-based registries. Follow-up data on mortality were obtained from the Danish Civil Registry System. RESULTS: Of 7,232 patients hospitalized for peptic ulcer bleeding, 28% were current non-steroidal anti-inflammatory drug users. Thirty-day mortality was 11% overall, and 13% among current non-steroidal anti-inflammatory drug users. Compared with never-use, the adjusted 30-day mortality rate ratios were 1.4 (95% CI: 1.1-1.9) for current use of non-steroidal anti-inflammatory drugs alone and 1.3 (95% CI: 1.0-1.7) for current use combined with other ulcer-related drugs. For users of celecoxib, alone and in combination, adjusted mortality rate ratios were 1.4 (95% CI: 0.5-3.9) and 2.0 (95% CI: 1.2-3.5), and for users of rofecoxib, 1.2 (95% CI: 0.4-3.9) and 0.9 (95% CI: 0.5-1.6). CONCLUSION: Among patients hospitalized with peptic ulcer bleeding, use of non-steroidal anti-inflammatory drugs, including some newer cyclo-oxygenase-2 inhibitors, is associated with increased short-term mortality.

Statins and the risk of acute pancreatitis: a population-based case-control study.

BACKGROUND: Case reports have suggested that statins may cause acute pancreatitis. AIM: To examine if statins are associated with risk of acute pancreatitis. METHODS: We identified 2576 first-time admitted cases of acute pancreatitis from hospital discharge registers in three Danish counties, and 25 817 age- and gender-matched controls from the general population. Prescriptions for statins prior to admission with acute pancreatitis or index date among controls were retrieved from prescription databases. We used conditional logistic regression analysis to estimate odds ratios for acute pancreatitis among ever (ever before), current (0-90 days before), new (first prescription in 0-90 days before) and former (>90 days, but not 0-90 days before) users of statins. RESULTS: Adjusted odds ratios for acute pancreatitis among ever, current, new and former users of statins were 1.44 (95% confidence interval: 1.115-1.80), 1.26 (95% confidence interval: 0.96-1.64), 1.01 (95% confidence interval: 0.43-2.37) and 2.02 (95% confidence interval: 1.37-2.97), respectively. There was an indication of an inverse association between the number of filled prescriptions and risk of acute pancreatitis. CONCLUSIONS: Our findings speak against a strong causative effect of statins on the risk of acute pancreatitis, and may even indicate a mild protective effect.

Parkinson's disease and other basal ganglia or movement disorders in a large nationwide cohort of Swedish welders.

INTRODUCTION: Although it has been hypothesised that metal welding and flame cutting are associated with an increased risk for Parkinson's disease due to manganese released in the welding fume, few rigorous cohort studies have evaluated this risk. METHODS: The authors examined the relation between employment as a welder and all basal ganglia and movement disorders (ICD-10, G20-26) in Sweden using nationwide and population based registers. All men recorded as welders or flame cutters (n = 49,488) in the 1960 or 1970 Swedish National Census were identified and their rates of specific basal ganglia and movement disorders between 1964 and 2003 were compared with those in an age and geographical area matched general population comparison cohort of gainfully employed men (n = 489,572). RESULTS: The overall rate for basal ganglia and movement disorders combined was similar for the welders and flame cutters compared with the general population (adjusted rate ratio (aRR) = 0.91 (95% CI 0.81 to 1.01). Similarly, the rate ratio for PD was 0.89 (95% CI 0.79 to 0.99). Adjusted rate ratios for other individual basal ganglia and movement disorders were also not significantly increased or decreased. Further analyses of Parkinson's disease by attained age, time period of follow up, geographical area of residency, and educational level revealed no significant differences between the welders and the general population. Rates for Parkinson's disease among welders in shipyards, where exposures to welding fumes are higher, were also similar to the general population (aRR = 0.95; 95% CI 0.70 to 1.28). CONCLUSION: This nationwide record linkage study offers no support for a relation between welding and Parkinson's disease or any other specific basal ganglia and movement disorders.

Cigarette smoking, alcohol, and nasopharyngeal carcinoma: a case-control study among U.S. whites.

BACKGROUND: Nasopharyngeal carcinoma (NPC) is a relatively uncommon cancer in the United States. Its etiology among White Americans is not well known, but cigarette smoking has been implicated in some epidemiologic studies. PURPOSE: The purpose of this study was to investigate the roles of cigarette use and alcohol consumption as risk factors for NPC in the United States. METHODS: We conducted a case-control study using data from the National Mortality Followback Survey based on information from death certificates. In this study, we compared use of cigarettes and alcohol by 204 White American men and women who died of NPC with that by 408 who died of causes unrelated to cigarette smoking and alcohol use. RESULTS: Risk of NPC increased in proportion to the amount and duration of smoking (with a more than threefold increase among persons smoking heavily) and declined following cessation of smoking. After controlling for smoking, we found an 80% excess risk of NPC among persons whose intake of alcohol was heavy. CONCLUSION: Use of cigarettes and consumption of alcohol were found to be statistically significant risk factors for NPC. The findings are among the strongest to date indicating that use of cigarettes and perhaps alcohol may contribute to the etiology of these relatively rare cancers among Whites in the United States.

Cancer risk after hip replacement with metal implants: a population-based cohort study in Sweden.

BACKGROUND: Joint replacement with metal implants has been the standard procedure for surgical treatment of irreversible degeneration of hip and knee joints for more than two decades. However, reports of local malignancy after joint replacement and experimental studies that suggest a carcinogenic action of metal ions and polymethylmethacrylate (an acrylic compound used to stabilize the implant in the host) have raised concern about the possible long-term risks associated with metal implants. PURPOSE: Our aim was to study cancer risk in a Swedish cohort of patients who had hip replacement surgery during the period 1965 through 1983. METHODS: We studied the risk of cancer in a cohort of 39 154 patients (14 869 men and 24 285 women), identified in the nationwide Swedish Inpatient Register with at least one hip replacement during the period 1965 through 1983. The patients were followed through 1989 by means of record linkage to the Swedish Cancer Register. The cohort contributed a total of 327 922 person-years at risk. Standardized incidence ratios (SIRs) were computed using age-, sex-, and period-specific incidence rates derived from the entire Swedish population. RESULTS: The overall relative risk of cancer was increased by only 3%. Bone cancer--the focus of previous concerns--occurred in six cases versus 4.3 expected, and connective tissue cancer occurred in 28 cases versus 25.9 expected. Increased risks were observed for kidney cancer (SIR = 1.31; 95% confidence interval [CI] = 1.13-1.51), prostate cancer (SIR = 1.13; 95% CI = 1.04-1.22), and melanoma (SIR = 1.23; 95% CI = 1.00-1.50). The relative risk of gastric cancer steadily declined with increasing follow-up time, in both men and women (SIR = 0.58; 95% CI = 0.39-0.84 more than 10 years after hip replacement). CONCLUSION: In this study, the largest study to date to evaluate hip replacement and subsequent cancer risk, the overall cancer risk appears to be negligible from a public health perspective, and our results have not produced any strong evidence against the continued use of these devices. Nevertheless, the small but statistically significant increases in kidney and prostate cancers and the decrease in gastric cancer deserve further study.

Reduced risk of esophageal cancer associated with green tea consumption.

BACKGROUND: Studies in laboratory animals have suggested inhibitory effects of green tea on the induction of some cancers, notably, esophageal cancer. However, only a few epidemiologic studies have evaluated green tea as a potential inhibitor of human esophageal cancer. PURPOSE: Our purpose was to evaluate the relationship between green tea consumption and the risk of esophageal cancer. METHODS: This esophageal cancer study was part of a larger multicenter, case-control study that included three other gastrointestinal sites (pancreas, colon, and rectum). Medical records of patients aged 30-74 years old who were diagnosed with esophageal cancer from October 1, 1990, through January 31, 1993, were identified from the Shanghai Cancer Registry, which covers 6.8 million people in the urban area of Shanghai, People's Republic of China. During the ascertainment period, records of 1016 eligible cases of esophageal cancer were identified. Control subject records were selected by frequency matching in accordance with the age-sex distribution of the four gastrointestinal cancers ascertained by the cancer registry during 1986-1987. Patient interviews were then conducted using a structured, standardized questionnaire to obtain information on demographic characteristics, residential history, height and weight, diet, smoking, alcohol and tea drinking, medical history, family history of cancer, occupation, physical activity, and reproductive history. RESULTS: Of the 902 patients interviewed, 734 (81.4%) had their disease pathologically confirmed. There were 1552 control subjects interviewed, including 240 alternates. All analyses of tea effects were conducted separately among men and women and all were adjusted for age. After further adjustment for other known confounders, a protective effect of green tea drinking on esophageal cancer was observed among women (odds ratio [OR] = 0.50; 95% confidence interval [CI] = 0.30-0.83), and this risk decreased (P for trend < or = .01) as tea consumption increased. Among men, the ORs were also below 1.00, although not statistically significant. ORs for green tea intake were estimated among those persons who neither smoked nor drank alcohol. In this subset, statistically significant decreases in risk among tea drinkers were observed for both men (OR = 0.43; 95% CI = 0.22-0.86; P for trend = .05) and women (OR = 0.40; 95% CI = 0.20-0.77; P for trend < .001). CONCLUSIONS: This population-based, case-control study of esophageal cancer in urban Shanghai suggests a protective effect of green tea consumption. Although these findings are consistent with studies in laboratory animals, indicating that green tea can inhibit esophageal carcinogenesis, further investigations are definitely needed.

Incidence of cancer among patients with rheumatoid arthritis.

BACKGROUND: To evaluate hypotheses about the relationship between immune alterations and cancer, several investigators have determined cancer incidence in groups of patients with rheumatoid arthritis (RA), a chronic autoimmune disease. The primary finding has been an increased risk of hematopoietic cancers. PURPOSE: In this study, we have attempted to refine estimates of the association between RA and subsequent development of specific cancers. METHODS: We investigated site-specific cancer risk associated with RA in a population-based cohort study of 11683 Swedish men and women with a hospital (inpatient) diagnosis of RA. These case patients were identified from 1965 to 1983 and had follow-up through 1984 by computer linkage of the Swedish Hospital Inpatient Register to the National Swedish Cancer Registry (840 case patients with cancer) and the Swedish Registry of Causes of Death. Cancer risk was estimated by standardized incidence ratios (SIRs) for specific cancers. RESULTS: For men and women overall, there were decreased risks for cancers of the colon (SIR = 0.63; 95% confidence interval [CI] = 0.5-0.9), rectum (SIR = 0.72; 95% CI = 0.5-1.1), and stomach (SIR = 0.63; 95% CI = 0.5-0.9) and an increased risk for lymphomas (SIR = 1.98; 95% CI = 1.5-2.6). CONCLUSIONS: The reduced risk for colorectal cancer in patients with RA is consistent with previous studies of RA patients and with reports which state that use of nonsteroidal anti-inflammatory drugs may protect against the development of large bowel cancers. The excess of lymphomas also confirms a number of earlier investigations of RA patients.

Pancreatitis and pancreatic cancer: a population-based study.

BACKGROUND: Little is known about the etiology of cancer of the exocrine portion of the pancreas, which produces a variety of digestive enzymes. Smoking, certain dietary factors, and diabetes mellitus are considered to be risk factors, although the risk estimates are modest in most instances. A recent cohort study of patients with chronic pancreatitis indicated a ninefold to 16-fold increased risk for pancreatic cancer. PURPOSE: Our purpose was to evaluate the relationship between various clinical types of pancreatitis and pancreatic cancer. METHODS: Data for this study were collected from all inpatient medical institutions in Sweden from 1965 until 1983 by the Swedish National Board of Health and Welfare. Data were recorded on individual hospital admissions and discharges in the Inpatient Register. All patients with records in the Inpatient Register coded for acute, chronic, or unspecified pancreatitis were considered for inclusion in the study. A population-based cohort of 7956 patients with at least one discharge diagnosis of pancreatitis was monitored (up to 19 years of follow-up) for the occurrence of pancreatic cancer by record linkages to the Swedish Cancer Registry and Registry of Causes of Death. RESULTS: A total of 46 pancreatic cancers were diagnosed during follow-up compared with 21 expected (standardized incidence ratio [SIR] of 2.2; 95% confidence interval [CI] 1.6-2.9) for the Uppsala Health Care Region. The excess risk for women and men was similar--most pronounced during the first period of follow-up (2-4 years) after discharge and close to unity after more than 10 years of follow-up. Patients with chronic pancreatitis and patients with more than one discharge diagnosis of either acute or unspecified pancreatitis were at higher risk (SIR = 3.8; 95% CI 1.4-8.2 and SIR = 4.8; 95% CI 1.9-9.9, respectively) compared with those with only one discharge of acute (SIR = 1.6; 95% CI 0.9-2.7) or unspecified (SIR = 2.1; 95% CI 1.2-3.2) pancreatitis. CONCLUSIONS: Our finding of a moderate excess of pancreatic cancer among patients with pancreatitis, especially the chronic or recurrent forms, supports some earlier clinical and case-control studies, but it is not consistent with the ninefold to 16-fold risk reported in a recent cohort study. The absence of an increased risk 10 years or more after first discharge for pancreatitis argues against a straight-forward causal relationship. Because of the relatively short interval between diagnosis of pancreatitis and pancreatic cancer, it is possible that some forms of pancreatitis are a precursor to pancreatic cancer or that shared risk factors for both diseases (e.g., cigarette smoking) may also be involved.

Protein intake and risk of renal cell cancer.

BACKGROUND: Renal cell cancer, although still relatively uncommon, has been increasing in incidence in the United States and other countries around the world. PURPOSE: Since previous studies have suggested an association with high intake of meat, we sought to further examine the role of diet in renal cell cancer risk. METHODS: Patients with histologically confirmed renal cell cancer that had been diagnosed between July 1, 1988, and December 31, 1990, were identified through the Minnesota Cancer Surveillance System, a statewide cancer registry. The patients eligible for inclusion in this study were white residents of Minnesota between 20 and 79 years of age. Control subjects were selected from the general population of Minnesota residents; subjects under age 65 were selected by use of a random-digit-dialing method and those 65 years or older were sampled from the Health Care Financing Administration files. Population-based control subjects were frequency-matched to cases by sex and 5-year age groups. A total of 690 patients and 707 control subjects were interviewed. Patients and control subjects were similar in distribution by sex, age, and educational level. Usual adult dietary intakes were assessed by questionnaire, and odds ratios were calculated by logistic regression analyses. RESULTS: Significantly increased risks of renal cell cancer were observed with increasing consumption of several food groups, including red meat (P for trend = .05), high-protein foods (P = .01), and staple (grains, breads, and potatoes) foods (P = .009). When examined by macronutrient status, risks increased monotonically with the amount of protein intake, from 1.2 (95% confidence interval [CI] = 0.7-1.9) to 1.4 (95% CI = 0.8-2.5) and 1.9 (95% CI = 1.0-3.6) (P for trend = .03) in the second, third, and fourth quartiles of intake, respectively, after adjustment for age, sex, caloric intake, body mass index, and cigarette smoking. No significant or consistent associations were detected with the intake of other dietary nutrients or beverages. CONCLUSION: Although an independent effect of dietary protein has not been previously associated with renal cell cancer, high protein consumption has been related to development of other chronic renal conditions that may predispose an individual to this cancer. IMPLICATION: These findings should prompt further study of dietary protein and its potential contribution to the origins of renal cell cancer.

Excess risk of primary liver cancer in patients with diabetes mellitus.

BACKGROUND: Chronic infection with hepatitis B virus, alcohol consumption, and cirrhosis of the liver are recognized risk factors for primary liver cancer. A few, but not all, studies have suggested that diabetes mellitus also increases risk for this cancer. PURPOSE: We conducted a population-based cohort study to analyze the risk of developing primary liver cancer and biliary tract (gallbladder, extrahepatic bile ducts, and ampulla of Vater) cancers among patients with diabetes. METHODS: A cohort of 153 852 patients with a hospital discharge diagnosis of diabetes in the period from 1965 through 1983 was identified by use of the Swedish In-patient Register. Follow-up for these patients extended from the date of cohort entry through December 31, 1989. Incident cases of cancer during follow-up were identified through the Swedish Cancer Registry. To minimize the impact of selection bias, we excluded from the analysis patients who were diagnosed with liver and biliary tract cancers during the first year of follow-up. Standardized incidence ratios (SIRs) and their 95% confidence intervals (CIs) were computed by use of nationwide rates of liver and biliary tract cancers, adjusted for age, sex, and calendar year, for comparison. RESULTS: During 1-24 years of follow-up, 819 incident cancers in the combined category of primary liver (n = 533) and biliary tract (n = 286) were identified in the cohort, yielding an overall SIR of 2.5 (95% CI = 2.3-2.6). The risk was higher in men (SIR = 3.2; 95% CI = 2.9-3.6) than in women (SIR = 2.0; 95% CI = 1.8-2.2). The incidence of primary liver cancer alone was increased fourfold (SIR = 4.1; 95% CI = 3.8-4.5); again, the risk was higher in men (SIR = 4.7; 95% CI = 4.2-5.2) than in women (SIR = 3.4; 95% CI = 2.9-3.9). Smaller increases in risk were seen for cancers of the gallbladder, the extrahepatic bile ducts, and the ampulla of Vater. After exclusion of diabetic patients with concomitant diseases that predispose to primary liver cancer, such as alcoholism, cirrhosis, and hepatitis, the persistence of an approximately threefold excess risk was observed. CONCLUSIONS: Our findings suggest that patients with diabetes are at increased risk of developing primary liver cancer and perhaps cancers of the biliary tract. The mechanisms involved in the association of diabetes and liver cancer remain to be clarified. Additional studies are needed to determine whether patients with insulin-dependent diabetes mellitus and those with non-insulin-dependent diabetes mellitus differ in their risk for primary liver cancer or whether the risk is affected by the type of diabetes treatment.

Nationwide study of cancer risk among hip replacement patients in Sweden.

BACKGROUND: Orthopedic implants and their fixatives contain materials with carcinogenic potential. Whether these implants are linked to subsequent cancer development remains unknown, mainly because large-scale, long-term follow-up data are scarce. METHODS: We conducted a nationwide cohort study in Sweden to examine cancer incidence among 116,727 patients who underwent hip replacement surgery during the period from 1965 through 1994. Through record linkage to the Swedish Cancer Register, we identified all incident cancers through 1995 in this population (693,954 person-years of observation). For each cancer type, the observed number of cases was divided by that expected in the general Swedish population to produce standardized incidence ratios (SIRs). RESULTS: Relative to the general population, the cohort had no overall cancer excess (SIR = 1.01; 95% confidence interval [CI] = 0.99 to 1.03). However, we observed elevated SIRs for prostate cancer (SIR = 1.16; 95% CI = 1.11 to 1.22) and melanoma (SIR = 1.15; 95% CI = 1.01 to 1.30) and a reduction in stomach cancer risk (SIR = 0.83; 95% CI = 0.75 to 0.92). Long-term follow-up (>or=15 years) revealed an excess of multiple myeloma (SIR = 1.86; 95% CI = 1.01 to 3.11) and a statistically nonsignificant increase in bladder cancer (SIR = 1.42; 95% CI = 0.98 to 1.99). There was no material increase in risk for bone or connective tissue cancer for either men or women in any follow-up period. CONCLUSIONS: In this, the largest study to date, hip implant patients had similar rates of most types of cancer to those in the general population. Although the excesses of melanoma, multiple myeloma, and prostate and bladder cancers may be due to chance, confounding, or detection bias and should be interpreted cautiously, they warrant further investigation because of the ever-increasing use of hip implants at younger ages.

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.

Etiology of cancer of the renal pelvis.

A population-based case--control interview study of cancer of the renal pelvis (74 cases and 697 controls) conducted in the Minneapolis--St. Paul metropolitan area showed cigarette smoking to be the major cause of this cancer. The odds ratio (OR) for cigarette smoking was 7.6 among males [95% confidence interval (CI): 2.2-31.5] and 5.8 among females (95% CI: 2.0-17.3), with the OR exceeding 10 for heavy smokers of both sexes. Long-term use of analgesics and several occupational exposures were also found to be risk factors. In addition, there were unexpected positive associations among females for heavy tea consumption and for use of estrogen medications, although the significance of these relationships remains to be 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.

Risk of urinary tract cancers following kidney or ureter stones.

BACKGROUND: A relationship has been suggested between kidney or ureter stones and the development of urinary tract cancers. In this study, a population-based cohort of patients hospitalized for kidney or ureter stones in Sweden was followed for up to 25 years to examine subsequent risks for developing renal cell, renal pelvis/ureter, or bladder cancer. METHODS: Data from the national Swedish In-patient Register and the national Swedish Cancer Registry were linked to follow 61,144 patients who were hospitalized for kidney or ureter stones from 1965 through 1983. Standardized incidence ratios (SIRs) and 95% confidence intervals (CIs) were computed on the basis of nationwide cancer incidence rates, after adjustment for age, sex, and calendar year. RESULTS: Risk of renal cell cancer was not elevated in this cohort. Significant excesses of renal pelvis/ureter cancer (SIR = 2.5; 95% CI = 1.8-3.3) and bladder cancer (SIR = 1.4; 95% CI = 1.3-1.6) were observed, but the SIRs for women were more than twice those for men. Risks varied little by age or duration of follow-up. Risks of renal pelvis/ureter cancer and bladder cancer among patients with an associated diagnosis of urinary tract infection were more than double those among patients without such infection, although the risks were significantly elevated in both groups. CONCLUSIONS: Individuals hospitalized for kidney or ureter stones are at increased risk of developing renal pelvis/ureter or bladder cancer, even beyond 10 years of follow-up. Chronic irritation and infection may play a role, since kidney or ureter stones were located on the same side of the body as the tumors in most patients with renal pelvis/ureter cancer evaluated in our study.