Does the method of Helicobacter pylori detection influence the association with gastric cancer risk?

BACKGROUND

The exact role of Helicobacter pylori as a causative agent of gastric cancer is still under debate. The aim of this study was to determine how the use of different diagnostic methods for detection of H. pylori influences the measures of prevalence of the infection and thus the association with risk of gastric adenocarcinoma.

METHODS

We included 72 cases and 324 controls in an endoscopy clinic-based matched case-control study. Culture of H. pylori and immunohistochemical staining were performed on gastric biopsies. Serum samples were tested for H. pylori IgG by conventional ELISA and by immunoblotting.

RESULTS

The overall prevalence of H. pylori was 68% based on all 4 diagnostic methods, 79% in the cases and 66% in the controls. Highest agreement, 91%, was observed between culture and immunohistochemistry with a Kappa value of 0.81. Immunoblotting detected the highest number of H. pylori-positive subjects in both cases and controls. The association of H. pylori positivity with gastric cancer was generally weaker and statistically non-significant using culture and immunohistochemistry compared with the serological tests, of which IgG ELISA yielded the higher odds ratio (OR 2.5, 95% confidence interval 1.4-4.4).

CONCLUSION

The study shows that relative risk estimates for the association between H. pylori and gastric cancer risk are to some extent determined by the diagnostic method used to detect H. pylori infection.

Occupational physical activity and risk for prostate cancer in a nationwide cohort study in Sweden

We investigated effects of occupational physical activity on relative risk for prostate cancer. From Swedish nationwide censuses in 1960 and 1970, we defined two cohorts of men whose occupational titles allowed classification of physical activity levels at work in 1960 (n=1,348,971) and in 1970 (n=1,377,629). A third cohort included only men whose jobs required a similar level of physical activity in both 1960 and 1970 (n=673,443). The incidence of prostate cancer between 1971 and 1989 was ascertained through record linkage to the Swedish Cancer Register. A total of 43,836, 28,702, and 19,670 prostate cancers, respectively, occurred in the three cohorts. In all three cohorts, the relative risk for prostate cancer increased with decreasing level of occupational physical activity (P<0.001), using Poisson regression. Among men with the same physical activity levels in 1960 and 1970, the rate ratio was 1.11 for men with sedentary jobs as compared with those whose jobs had very high/high activity levels after adjustment for age at follow-up, calendar year of follow-up and place of residence (95% CI 1.05-1.17; P for trend <0.001). There was no association between occupational activity and prostate cancer mortality. Since we had no data on other potential risk factors the observed associations for both incidence and mortality might have been confounded. Further studies are needed to better understand the potential role of physical activity for prostate cancer.

Reflux-inducing dietary factors and risk of adenocarcinoma of the esophagus and gastric cardia

Gastroesophageal reflux (GER) is the strongest known risk factor for esophageal adenocarcinoma. For long-term sufferers with severe symptoms, the excess risk may exceed 40-fold. GER has also been shown to increase the risk of cancers of the gastric cardia more than fourfold. Several foods, including dietary fat, chocolate, mints, coffee, onions, citrus fruit, and tomatoes, have been associated with temporary symptoms of reflux, most likely through a relaxation of the lower esophageal sphincter (LES). Our aim was to determine whether these foods are associated with risk of adenocarcinoma of the esophagus or gastric cardia. We studied intakes of LES-relaxing foods and other dietary habits potentially associated with reflux in a nationwide population-based case-control study in Sweden, with 185 and 258 cases of esophageal adenocarcinoma and gastric cardia adenocarcinoma, respectively, and 815 controls. We found no association between LES-relaxing foods and symptoms of chronic reflux, although this might be due to avoidance of these foods among sufferers. In addition, we found no association between dietary factors known to cause LES relaxation and the risk of adenocarcinoma of the esophagus or gastric cardia. Our findings indicate that dietary factors associated with LES relaxation and transient GER (but perhaps not severe chronic reflux) are not associated with any important risk of esophageal malignancy.

Acetaminophen, aspirin, and chronic renal failure

BACKGROUND

Several epidemiologic studies have demonstrated an association between heavy consumption of nonnarcotic analgesics and the occurrence of chronic renal failure, but it is unclear which is the cause and which is the effect

METHODS

In a nationwide, population-based, case-control study of early-stage chronic renal failure in Sweden, face-to-face interviews were conducted with 926 patients with newly diagnosed renal failure and 998 control subjects, of whom 918 and 980, respectively, had complete data. We used logistic-regression models to estimate the relative risks of disease-specific types of chronic renal failure associated with the use of various analgesics

RESULTS

Aspirin and acetaminophen were used regularly by 37 percent and 25 percent, respectively, of the patients with renal failure and by 19 percent and 12 percent, respectively, of the controls. Regular use of either drug in the absence of the other was associated with an increase by a factor of 2.5 in the risk of chronic renal failure from any cause. The relative risks rose with increasing cumulative lifetime doses, rose more consistently with acetaminophen use than with aspirin use, and were increased for most disease-specific types of chronic renal failure. When we disregarded the recent use of analgesics, which could have occurred in response to antecedents of renal disease, the associations were only slightly attenuated

CONCLUSIONS

Our results are consistent with the existence of exacerbating effects of acetaminophen and aspirin on chronic renal failure. However, we cannot rule out the possibility of bias due to the triggering of analgesic consumption by predisposing conditions.

Risk of adenocarcinomas of the esophagus and gastric cardia in patients with gastroesophageal reflux diseases and after antireflux surgery

BACKGROUND & AIMS

Gastroesophageal reflux has been proposed as an important risk factor for esophageal and gastric cardia adenocarcinoma, but prospective data are lacking. Furthermore, the effect of antireflux surgery has not yet been studied. We conducted a population-based retrospective cohort study to fill these gaps.

METHODS

A cohort of 35,274 male and 31,691 female patients with a discharge diagnosis of gastroesophageal reflux diseases, and another cohort of 6406 male and 4671 female patients who underwent antireflux surgery, were identified in the Swedish Inpatient Register. Follow-up was attained through record linkage with several nationwide registers. Standardized incidence ratio (SIR) was used to estimate relative risk of upper gastrointestinal cancers, using the general Swedish population as reference.

RESULTS

After exclusion of the first year follow-up, 37 esophageal and 36 gastric cardia adenocarcinomas were observed among male patients who did not have surgery (SIR, 6.3, 95% confidence interval [CI], 4.5-8.7; SIR, 2.4, 95% CI, 1.7-3.3, respectively). SIR for esophageal adenocarcinoma increased with follow-up time (P = 0.03 for trend). Among male patients who had undergone antireflux surgeries, risks were also elevated (16 esophageal adenocarcinoma, SIR, 14.1, 95% CI, 8.0-22.8; 15 gastric cardia adenocarcinomas, SIR, 5.3, 95% CI, 3.0-8.7) and remained elevated with time after surgery. The cancer risk pattern in women was similar to that for men, but the number of cases were much smaller.

CONCLUSIONS

Gastroesophageal reflux is strongly associated with the risk of esophageal adenocarcinoma, and to a lesser extent, with gastric cardia adenocarcinoma. The risk of developing adenocarcinomas of the esophagus and gastric cardia remains increased after antireflux surgery.

Incidence of lung cancer in a large cohort of non-smoking men from Sweden

Valid data on the occurrence of lung cancer among non-smokers are sparse and refer mainly to North American populations. The objective of our study is to provide an estimate of the incidence of lung cancer among non-smokers in a large European population. Proceeding from a nation-wide health care program among Swedish construction workers, we estimated the incidence of lung cancer among 143,998 males who reported to be never smokers at 1 or several physical check-ups (average, 2.9 visits) during 1971-92. Cancer incidence data for 1971-95 were obtained through linkage with the virtually complete national cancer registry. Cohort members contributed over 2 million person-years of observation, during which 101 lung cancers occurred. The age-standardized rate was 3.7/100,000 (95% confidence interval [CI] 2.8-4.6). There was a suggestion of a calendar period effect, with rates increasing from 1.5/100,000 in 1976-80 to 5.4/100,000 in 1991-95. A birth cohort effect was also suggested. Rates estimated in this population are comparable to those from North American studies. The increasing rate during the study period might be due to non-smokers who took up the habit, but it might also reflect temporal changes in the effect of other risk factors of lung cancer in non-smokers.

Risk of adenocarcinomas of the oesophagus and gastric cardia in patients hospitalized for asthma

In the first cohort study of the question we followed 92 986 (42 663 men and 50 323 women) adult patients hospitalized for asthma in Sweden from 1965 to 1994 for an average of 8.5 years to evaluate their risk of oesophageal and gastric cardia adenocarcinoma. Standardized incidence ratio (SIR) adjusted for gender, age and calendar year was used to estimate relative risk, using the Swedish nationwide cancer incidence rates as reference. Asthmatic patients overall had a moderately elevated risk for oesophageal adenocarcinoma (SIR = 1.5, 95% confidence interval CI, 0.9-2.5) and gastric cardia cancer (SIR = 1.4, 95% CI, 1.0-1.9). However, the excess risks were largely confined to asthmatic patients who also had a discharge record of gastro-oesophageal reflux (SIR = 7.5, 95% CI, 1.6-22.0 and SIR = 7.1, 95% CI, 3.1-14.0, respectively). No significant excess risk for oesophageal squamous-cell carcinoma or distal stomach cancer was observed. In conclusion, asthma is associated with a moderately elevated risk of developing oesophageal or gastric cardia adenocarcinoma. Special clinical vigilance vis-à-vis gastro-esophageal cancers seems unwarranted in asthmatic patients, but may be appropriate in those with clinically manifest gastro-oesophageal reflux.

Risk of pancreatic cancer after cholecystectomy: a cohort study in Sweden

BACKGROUND

Although some experimental studies have indicated that cholecystectomy may increase the risk of pancreatic cancer, data from epidemiological studies are conflicting.

AIMS

We conducted a register based retrospective cohort study to explore the relationship between cholecystectomy and pancreatic cancer.

SUBJECTS

The cohort included 87 263 men and 181 049 women with a documented cholecystectomy for cholelithiasis between 1965 and 1997.

METHODS

By record linkage to the nationwide and virtually complete registers of Cancer, Emigration, and Causes of Death, the cohort was followed up until the occurrence of any cancer, emigration, death, or the end of follow up, 31 December 1997, whichever came first. Relative risk was estimated by standardised incidence ratio (SIR) using the Swedish nationwide sex, age, and calendar year specific cancer incidence rates as reference.

RESULTS

During the period of observation, 1053 cases of pancreatic cancer were found, among which 231 (22%) occurred within 12 months after operation. After excluding cases and person years accrued during the first two years of follow up, we observed a non-significant 6% excess risk for pancreatic cancer (95% confidence interval (CI) -2 to 14%). The relative risk did not increase with increasing follow up duration, with a SIR equal to 0.98 (95% CI 0.79-1.20) 20 years or more after operation. Patients with a comorbidity of diabetes or chronic pancreatitis had higher relative risks (SIR=1.79, 95% CI 1.39-2.28; SIR=3.17, 95% CI 1.37-6.24, respectively). After excluding patients with recorded diabetes or chronic pancreatitis, the relative risk was close to unity (SIR=1.01, 95% CI 0.94-1.09).

CONCLUSIONS

Our findings do not support the hypothesis that cholecystectomy increases the subsequent risk of pancreatic cancer.

Primary brain tumors following traumatic brain injury--a population-based cohort study in Sweden

OBJECTIVES

The aim of this study was to explore the association between traumatic brain injury and brain tumor development.

METHODS

A cohort of patients hospitalized for traumatic brain injury during 1965-1994 was compiled using the Swedish Inpatient Register. Complete follow-up through 1995 was attained through record linkage with the Swedish Cancer Register, the Cause of Death Register, and the Emigration Register. Standardized incidence ratios (SIRs), defined as the ratios of the observed to the expected numbers of brain tumors, were used as the measure of relative risk. The expected number of brain tumors was calculated by multiplying the observed person-time by age-, gender- and calendar year-specific incidence-rates derived from the general Swedish population.

RESULTS

The cohort included 311,006 patients contributing 3,225,317 person-years. A total of 281 cases of brain tumors were diagnosed during follow-up. No associations were found between traumatic brain injury and the risk of primary brain tumors, neither overall (SIR: 1.0; 95% confidence interval (CI): 0.9-1.2), nor in analyses broken down by main groups of brain tumors. Stratified analyses according to age at entry into the cohort, year of follow-up, and severity of the brain injury all showed essentially the same null results.

CONCLUSION

No association between traumatic head injury and primary brain tumors has been found.

Helicobacter pylori in gastric cancer established by CagA immunoblot as a marker of past infection

BACKGROUND & AIMS

Helicobacter pylori may disappear spontaneously with progressing precancerous changes and invalidate serologic studies of its association with gastric cancer. We reestimated the strength of the H. pylori-gastric cancer relationship, using both conventional immunoglobulin (Ig) G enzyme-linked immunosorbent assay (ELISA) and immunoblot (against cytotoxin-associated antigen A [CagA] antibodies that prevail longer after eradication) to detect past H. pylori exposure more relevant for time at cancer initiation.

METHODS

In our population-based case-control study, the seroprevalence among 298 gastric adenocarcinoma cases was 72% (IgG ELISA) and 91% (immunoblot) vs. 55% and 56% among 244 controls frequency-matched for age and gender.

RESULTS

Using IgG ELISA only, the adjusted OR for noncardia gastric cancer among H. pylori-positive subjects was 2.2 (95% confidence interval [CI], 1.4-3.6). When ELISA-/CagA+ subjects (odds ratio [OR], 68.0) were removed from the reference, the OR rose to 21.0 (95% CI, 8.3-53.4) and the previous effect modification by age disappeared. ELISA+/CagA- subjects had an OR of 5.0 (95% CI, 1.1-23.6). There were no associations with cardia cancer.

CONCLUSIONS

The weaker H. pylori-cancer relationships in studies based on IgG ELISA rather than CagA may be caused by misclassification of relevant exposure. A much stronger relationship emerges with more accurate exposure classification. In the general Swedish population, 71% of noncardia adenocarcinomas were attributable to H. pylori.

The risk of liver and bile duct cancer in patients with chronic viral hepatitis, alcoholism, or cirrhosis

No prospective study has analyzed simultaneously chronic viral hepatitis and alcoholism as risk factors for liver carcinogenesis, while taking into consideration the role of cirrhosis. Nor has the risk for hepatocellular carcinoma among patients with chronic viral hepatitis been prospectively evaluated in a low-risk Western population. Last, the relationship between hepatocellular carcinoma risk factors and bile duct cancer remains to be clarified. We analyzed prospectively the risk for primary liver and extrahepatic biliary tract cancer among 186,395 patients hospitalized with either chronic viral hepatitis, alcoholism, cirrhosis, or any combination of these conditions through linkages between national Swedish registers. Compared with the general population, the relative risk of hepatocellular carcinoma was 34.4 for chronic viral hepatitis alone, 2.4 for alcoholism alone, and 40.7 for cirrhosis alone. Among patients with combinations of these risk conditions, the relative risk of hepatocellular carcinoma was 27.3 for chronic viral hepatitis and alcoholism, 118.5 for chronic viral hepatitis and cirrhosis, 22.4 for alcoholism and cirrhosis, and 171.4 for all 3 conditions. We found limited evidence for an excess risk of intrahepatic, but not for extrahepatic, biliary duct cancer. Cirrhosis amplifies the risk of hepatocellular carcinoma among patients with chronic viral hepatitis, but it is not a prerequisite for liver carcinogenesis. In contrast, cirrhosis may be a necessary intermediate for the development of hepatocellular carcinoma among alcoholics.

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.

Breast cancer risk in male alcoholics in Sweden

OBJECTIVE

To investigate the association between alcoholism and risk of male breast cancer.

METHODS

We conducted a retrospective population-based cohort study in Sweden of men diagnosed with alcoholism between 1965 and 1995. The cohort was followed up through interlinkages with nationwide registries (the national cancer registry, immigration registry, causes of death registry, and population registry), using the national registration numbers. Standardized incidence ratios (SIRs), calculated using the Swedish national cancer incidence rate as reference, were used as estimates of relative risks.

RESULTS

A total of 145,811 men were enrolled into the cohort, contributing 1,499,504 person-years of follow-up. Sixteen incident breast cancer cases were identified, and the mean age at diagnosis was 68 years. We excluded the first year of follow-up (cases and person-years) from the analysis to avoid detection bias. The overall SIR (excluding the first year of follow-up) was 1.1 (95% CI 0.6-2.0). Although based on small numbers we found no indication of a differential SIR according to duration of follow-up, age at cohort enrolment, or age at follow-up (attained age or age at cancer diagnosis).

CONCLUSION

The observed associations are not compatible with an increase in breast cancer risk among male alcoholics.

Risk of cancers of the lung, head and neck in patients hospitalized for alcoholism in Sweden

Alcoholic patients are at increased risk of cancers of the head and neck but little information is available on the magnitude of the risk for specific sites and for different histological types. We followed 182 667 patients with a hospital discharge diagnosis of alcoholism during 1965-1994, for an average of 10.2 years. We compared their incidence of site- and histological type-specific cancers of the oral cavity, pharynx, larynx and lung with that of the national population. The standardized incidence ratio (SIR) of cancer of the oral cavity and pharynx was 5.33 (95% confidence interval [CI] 5.04-5.64, based on 1207 cases). The SIRs of laryngeal and lung cancer were 4.21 (95% Cl 3.78-4.68, 347 cases) and 2.40 (2.29-2.51, 1880 cases), respectively. The SIR was highest for cancers of the hypopharynx, floor of the mouth, mesopharynx and base of the tongue. The relative excess of lung cancer was similar for squamous cell carcinoma and adenocarcinoma. Low age at first hospitalization was associated with higher SIRs for all sites under study. 25 years after first hospitalization for alcoholism, the cumulative probability of developing a lung cancer was in the order of 5%, for oral and pharyngeal cancer it was 2.5%, and for oesophageal or laryngeal cancer 1% each. Our study shows that the risk of head and neck cancer among heavy drinkers is highest for sites in direct contact with alcohol. The high risk of head and neck neoplasms may justify specific medical attention.

Fruit and vegetable consumption in the prevention of oesophageal and cardia cancers

The incidence of adenocarcinoma of the oesophagus has increased rapidly in recent decades. In order to appreciate the potential for prevention by means of dietary modification, we estimated the aetiological fractions and the increments in absolute risk attributable to low intake of fruit and vegetables for adenocarcinoma and squamous cell carcinoma of the oesophagus and for adenocarcinoma of the gastroesophageal junction. We conducted a nationwide population-based case-control study in Sweden, with participation of 608 cases and 815 controls. We used unconditional logistic regression to estimate relative risks, from which we calculated aetiological fractions. Individuals in the highest exposure quartile (median 4.8 servings/day) versus the lowest (median 1.5 servings/day) showed approximately 50% lower risk of oesophageal adenocarcinoma and 40% lower risk of oesophageal squamous cell carcinoma, but no risk reduction for gastric cardia adenocarcinoma. Approximately 20% of oesophageal adenocarcinoma, and likewise squamous cell carcinoma, in Sweden was attributed to consuming less than three servings of fruit and vegetables per day. A very large number of individuals (over 25,000) would need to increase their fruit and vegetable consumption moderately in order to prevent one oesophageal cancer per year. Moderate relative risk reductions translate into weak absolute risk reductions for oesophageal cancers in Sweden.

Helicobacter pylori infection in Swedish school children: lack of evidence of child-to-child transmission outside the family

BACKGROUND & AIMS

Helicobacter pylori infection is mainly acquired in early childhood, but the exact routes of transmission remain elusive. To distinguish between risks of intrafamilial and extraneous child-to-child transmission, we studied H. pylori seroprevalence among Swedish school children with varying family backgrounds.

METHODS

In a cross-sectional study, 695 of 858 (81%) 10-12-year-olds in 36 school classes in Stockholm donated blood and answered a questionnaire. Infection was detected by enzyme-linked immunosorbent assay and confirmed by immunoblot and urea breath test.

RESULTS

Overall, 112 (16%) children were infected. The seroprevalence was 2% among 435 children with Scandinavian parents and 55% among 144 children with origin in high prevalence areas (Middle East and Africa). Among children born in Scandinavia, the odds ratios (adjusted for gender, socioeconomic status, and family size) for being seropositive were 39.1 (95% confidence interval, 16.7-91.3) and 5.6 (1.8-17.3) when having parents born in high and medium prevalence areas, respectively, relative to children with Scandinavian parents. Importantly, the prevalence of infection among the classmates was not a risk factor for H. pylori infection.

CONCLUSION

Our data indicate that intrafamilial transmission is far more important than child-to-child transmission outside the family. The H. pylori prevalence in the parental generation may be a crucial determinant for the child's risk of contracting the infection.

Cause-specific mortality in a cohort of patients with diabetes mellitus: a population-based study in Sweden

A cohort of patients with diabetes mellitus hospitalised in Sweden from 1965 to 1983 was followed up until 1989, by linkages of population-based registers. Standardised mortality ratios (SMR), adjusted for confounding variables, and 95% confidence intervals (CIs) were calculated. After exclusion of the first year of follow-up (to reduce the effect of selection bias), the cohort consisted of 144,427 patients, of whom 92,248 patients died during follow-up. The SMR for all causes of death combined was 2.62 (95% CI 2.58-2.67) among men and 3.23 (95% CI 3.18-3.28) among women. The excess mortality was still evident 20 years after first hospitalisation, but became less marked with longer follow-up time. Patients with presumably insulin-dependent diabetes mellitus (IDDM) had the highest SMRs (10.2; CI 9.5-11.0); however, there was a significant (34%) improvement over time in their mortality risk. We conclude that excess mortality persisted throughout all calendar periods and at all ages, indicating the need for health care prevention measures.

Alcoholism and risk for endometrial cancer

Endogenous estrogens increase the risk of endometrial cancer and are also elevated among women with high alcoholic intake. It is incompletely known, however, whether alcohol intake in general and alcohol abuse in particular increases risk for endometrial cancer. We thus analyzed prospectively the risk for endometrial cancer among 36,856 women hospitalized with alcoholism between 1965 and 1994 through linkages between several national Swedish registers. Compared with the general population, women who were alcoholics had an overall 24% lower risk of developing endometrial cancer, a finding challenging our a priori hypothesis. However, among women below the age of 50 years at follow-up, the mean age of menopause among Swedish women, the risk was 70% higher, whereas the risk among women aged 50 years or more at follow-up was 40% lower compared with the general population. Hence, the effect of alcoholism on endometrial cancer appears to be age dependent.

Incidence of cancer among patients with hidradenitis suppurativa

BACKGROUND

On the basis of some case reports, a relationship has been suggested between hidradenitis suppurativa (HS) and the development of nonmelanoma skin cancer.

OBJECTIVES

To confirm this relationship and to explore the risk of other cancers among patients with HS.

PATIENTS

Patients with a discharge diagnosis of HS were obtained from the computerized database of hospital discharge diagnoses from January 1, 1965, through December 31, 1997. A total of 2119 patients with HS were identified.

SETTING

All hospitals in Sweden.

DESIGN

With record linkage to the Swedish National Cancer Registry, standardized incidence ratios (SIR [the ratio of the observed to expected incidence]) were calculated to estimate relative risk.

RESULTS

The risk of developing any cancer in the cohort with HS increased 50% (95% confidence interval of SIR, 1.1-1.8, based on 73 observed cases). Statistically significant risk elevations were observed for nonmelanoma skin cancer (5 cases; SIR, 4.6; 95% confidence interval, 1.5-10.7), buccal cancer (5 cases; SIR, 5.5; 95% confidence interval, 1.8-12.9), and primary liver cancer (3 cases; SIR, 10.0; 95% confidence interval, 2.1-29.2).

CONCLUSIONS

This study confirms an increased risk of nonmelanoma skin cancer among patients with HS. The risk for buccal cancer and primary liver cancer was also elevated among this cohort, but these associations should be interpreted cautiously because the combination of multiple significance testing and the few observed cases may have generated chance findings.

Aspirin and risk for gastric cancer: a population-based case-control study in Sweden

While aspirin and other non-steroid anti-inflammatory drugs (NSAIDs) are associated with gastric mucosal damage, they might reduce the risk for gastric cancer. In a population-based case-control study in 5 Swedish counties, we interviewed 567 incident cases of gastric cancer and 1165 controls about their use of pain relievers. The cases were uniformly classified to subsite (cardia/non-cardia) and histological type and information collected on other known risk factors for gastric cancer. Helicobacter pylori serology was tested in a subset of 542 individuals. Users of aspirin had a moderately reduced risk of gastric cancer compared to never users; odds ratio (OR) adjusted for age, gender and socioeconomic status was 0.7 (95% CI = 0.6-1.0). Gastric cancer risk fell with increasing frequency of aspirin use (P for trend = 0.02). The risk reduction was apparent for both cardia and non-cardia tumours but was uncertain for the diffuse histologic type. No clear association was observed between gastric cancer risk and non-aspirin NSAIDs or other studied pain relievers. Our finding lends support to the hypothesis that use of aspirin reduces the risk for gastric cancer.

Gastric cancer and human leukocyte antigen: distinct DQ and DR alleles are associated with development of gastric cancer and infection by Helicobacter pylori

DNA and sera from 130 cases of gastric cancer and 263 population-based controls were analyzed to study the association of HLA class II DR-DQ alleles with Helicobacter pylori (Hp) infection and the risk for gastric cancer. Presence of the DQA1*0102 allele was inversely and significantly associated with Hp seropositivity (P = 2 x 10(-5)), which is an independent replication of previous findings. However, this inverse relationship with Hp did not correspond with a reduced risk of gastric cancer. At the DRB1 locus, the *1601 allele was significantly associated with an increased gastric cancer risk with an odds ratio (95% confidence interval) of 8.7 (range, 2.7-28.0). The effect of *1601 was more pronounced among Hp-negative subjects, and the association was stronger with the diffuse, rather than with the intestinal, histological type of gastric cancer. Because none of the HLA alleles were associated with both Hp infection and gastric cancer, the HLA DR-DQ alleles are linked with gastric cancer risk through other mechanisms than an increased susceptibility to Hp infection.

Offspring health risk after cosmetic breast implantation in Sweden

Case reports have suggested that children born to women with silicone breast implants may have an excess risk of rheumatic disease and/or esophageal disorders. In Sweden, the authors conducted a retrospective cohort study of 5,874 children born to women with cosmetic breast implants and 13,274 children born to women who had breast reduction surgery. Using national registers, they computed hospitalization rates for rheumatic and esophageal disorders, incidence rates for cancer, and prevalence rates for congenital malformations and perinatal death. Relative to children of women who had breast reduction surgery, children born to women who had cosmetic breast implants were not at excess risk of rheumatic disease (relative risk [RR] = 1.1; 95% confidence interval [95% CI], 0.2-5.3), esophageal disorders (RR = 1.0; 95% CI, 0.7-1.6), cancer (RR = 0.3; 95% CI, 0.0-2.5), congenital malformations in total (RR = 1.0; 95% CI, 0.6-1.5), or specifically involving the digestive organs (RR = 0.5; 95% CI, 0.2-1.3) or perinatal death (RR = 0.9; 95% CI, 0.5-1.8). The rates of these health outcomes among children born after a mother's implant surgery were also not significantly higher than among children born before a mother's implant surgery. This study provides no evidence that certain hypothesized health outcomes are more likely among the children of women with cosmetic breast implants.

Inverse association between intake of cereal fiber and risk of gastric cardia cancer

BACKGROUND & AIMS

Recent data show that salivary nitrites form carcinogenic nitrosamines, especially at the gastric cardia. Wheat fiber has been shown to neutralize such mutagen formation. Our aim was to evaluate the association between dietary fiber and cancers of the esophageal and gastric cardia.

METHODS

We examined data from a large-scale population-based case-control study of risk factors for adenocarcinoma of the gastric cardia and esophagus and squamous cell carcinoma of the esophagus.

RESULTS

We found a strong dose-dependent inverse association between total dietary fiber intake and risk of gastric cardia adenocarcinoma, which was driven mainly by intake of cereal fiber. The odds ratio among individuals in the highest quartile of cereal fiber intake compared with the lowest was 0.3 (95% confidence interval, 0.2-0.5; P trend < 0.0001). High intake of cereal fiber was also associated with a moderately decreased risk of esophageal adenocarcinoma, but no linear dose-risk trend was observed. There was no association between dietary fiber and esophageal squamous cell carcinoma.

CONCLUSIONS

High intake of cereal fiber may significantly lower the risk of gastric cardia cancer.

Inverse association between intake of cereal fiber and risk of gastric cardia cancer

BACKGROUND & AIMS

Recent data show that salivary nitrites form carcinogenic nitrosamines, especially at the gastric cardia. Wheat fiber has been shown to neutralize such mutagen formation. Our aim was to evaluate the association between dietary fiber and cancers of the esophageal and gastric cardia.

METHODS

We examined data from a large-scale population-based case-control study of risk factors for adenocarcinoma of the gastric cardia and esophagus and squamous cell carcinoma of the esophagus.

RESULTS

We found a strong dose-dependent inverse association between total dietary fiber intake and risk of gastric cardia adenocarcinoma, which was driven mainly by intake of cereal fiber. The odds ratio among individuals in the highest quartile of cereal fiber intake compared with the lowest was 0.3 (95% confidence interval, 0.2-0.5; P trend < 0.0001). High intake of cereal fiber was also associated with a moderately decreased risk of esophageal adenocarcinoma, but no linear dose-risk trend was observed. There was no association between dietary fiber and esophageal squamous cell carcinoma.

CONCLUSIONS

High intake of cereal fiber may significantly lower the risk of gastric cardia cancer.

[Feedback on prescribing profiles at a primary health center. Important element in quality assurance of drug prescription]

DU90%--the number of drugs that account for 90% of DDDs--and adherence to guidelines in this segment were proposed by the Swedish Medical Quality Council (MKR) as indicators for assessing the quality of drug prescribing. We tested these indicators at a primary health care (PHC) center in Stockholm. Bar-coded prescriptions purchased at pharmacies were compared with the guidelines issued by the regional drug committee. The data were presented and discussed at the PHC center. Although the DU90% method neither examines the appropriateness of use nor provides outcome data, it was shown to be an inexpensive, flexible and simple method for assessing the general quality of drug prescribing.