Post-transfusion mortality among recipients of ABO-compatible but non-identical plasma

BACKGROUND AND OBJECTIVES

The consequences of ABO-compatible non-identical plasma for patient outcome have not been studied in randomized clinical trials or large cohort studies and use varies widely in the absence of evidence-based policies. We investigated if transfusion with compatible instead of identical plasma confers any short-term survival disadvantage on the recipients.

MATERIALS AND METHODS

The cohort of all 86 082 Swedish patients who received their first plasma transfusion between 1990 and 2002 was followed for 14 days and the risk of death in patients exposed to compatible non-identical plasma compared to recipients of only identical plasma.

RESULTS

After adjustment for potential confounding factors, there was an increased mortality associated with exposure to ABO-compatible non-identical plasma, with the excess risk mostly confined to those receiving 5 or more units (relative risk, 1.15; 95% confidence interval, 1.02-1.29). Stratification by blood group indicated higher risks in group O recipients, especially when the compatible plasma was from a group AB donor.

CONCLUSIONS

This study suggests that ABO-compatible non-identical plasma is less safe than identical plasma. Subanalyses by blood group suggest a role for circulating immune complexes. Our findings may have policy implications for improving transfusion safety.

Blood transfusion exposure in Denmark and Sweden

BACKGROUND

Although essential for the evaluation of blood transfusion safety, the prevalence of blood transfusion in the general population is not presently known. This study estimated the exposure to blood transfusion in the general Scandinavian population.

STUDY DESIGN AND METHODS

Population-based registry data of more than 600,000 transfusion recipients and general population data from 2000 to 2002 in Denmark and 1996 to 2002 in Sweden were reviewed. Outcome measures were the unit exposure rate, the 1-year period prevalence, the incidence rate, and the prevalence of exposure to blood transfusion.

RESULTS

The unit exposure rate was 71.9 per 1000 population per year in Denmark and 60.9 in Sweden, corresponding to 29 percent more blood units being transfused in Denmark than in Sweden. The 1-year period prevalence was 8.8 and the incidence rate was 7.2 per 1000 population per year in Denmark, being 37 and 25 percent higher than in Sweden, respectively. The prevalences of blood transfusion in Danish males at 20, 40, 60, and 80 years of age were 1.9, 3.1, 7.6, and 18.1 percent, respectively. In Danish females, the corresponding prevalences were 1.6, 5.9, 11.1, and 20.5 percent. A similar but slightly lower prevalence was found in Sweden.

CONCLUSION

Exposure to blood transfusion is frequent in Denmark and Sweden. At age 80 years, approximately one in five persons in the general population had received blood at least once.

Acetaminophen, aspirin and progression of advanced chronic kidney disease

BACKGROUND

Although many studies have investigated the possible association between analgesic use (acetaminophen and aspirin) and the development of chronic kidney disease (CKD), the effect of analgesics on the progression of established CKD of any cause has not yet been investigated.

METHODS

In this population-based Swedish cohort study, we investigated the decline over 5-7 years in estimated glomerular filtration rate (eGFR) among 801 patients with incident, advanced CKD (serum creatinine >3.4 mg/dL for men, >2.8 mg/dL for women for the first time) and with different analgesic exposures. Lifetime analgesic use and current regular use were ascertained through in-person interviews at inclusion while data on analgesic use during the follow-up was abstracted from the medical records at the end of the study period. A linear regression slope, based on their eGFR values during the follow-up, provided a summary of within-individual change. In the final multivariate analyses, a linear mixed effects model was implemented to assess the relation of analgesic use and change in eGFR over time.

RESULTS

The progression rate for regular users of acetaminophen was slower than that for non-regular users (regular users progressed 0.93 mL/min/1.73 m(2) per year slower than non-regular users; 95% CI 0.03, 1.8). For regular users of aspirin, the progression rate was significantly slower than that for non-regular users (regular users progressed 0.80 mL/min/1.73 m(2) per year slower than non-regular users; 95% CI 0.1, 1.5). Different levels of lifetime cumulative dose of acetaminophen and aspirin did not significantly affect the progression rate.

CONCLUSION

We suggest that single substance acetaminophen and aspirin may be safe to use by patients with diagnosed advanced CKD stage 4-5 without an adverse effect on the progression rate of the disease.

A 9-year follow-up study of participants and nonparticipants in sigmoidoscopy screening: importance of self-selection

BACKGROUND

Self-selection may compromise cost-effectiveness of screening programs. We hypothesized that nonparticipants have generally higher morbidity and mortality than participants.

METHODS

A Swedish population-based random sample of 1,986 subjects ages 59 to 61 years was invited to sigmoidoscopy screening and followed up for 9 years by means of multiple record linkages to health and population registers. Gender-adjusted cancer incidence rate ratio (IRR) and overall and disease group-specific and mortality rate ratio (MRR) with 95% confidence intervals (95% CI) were estimated for nonparticipants relative to participants. Cancer and mortality rates were also estimated relative to the age-matched, gender-matched, and calendar period-matched Swedish population using standardized incidence ratios and standardized mortality ratios.

RESULTS

Thirty-nine percent participated. The incidence of colorectal cancer (IRR, 2.2; 95% CI, 0.8-5.9), other gastrointestinal cancer (IRR, 2.7; 95% CI, 0.6-12.8), lung cancer (IRR, 2.2; 95% CI, 0.8-5.9), and smoking-related cancer overall (IRR, 1.4; 95% CI, 0.7-2.5) tended to be increased among nonparticipants relative to participants. Standardized incidence ratios for most of the studied cancers tended to be >1.0 among nonparticipants and <1.0 among participants. Mortality from all causes (MRR, 2.4; 95% CI, 1.7-3.4), neoplastic diseases (MRR, 1.9; 95% CI, 1.1-3.5), gastrointestinal cancer (MRR, 4.7; 95% CI, 1.1-20.7), and circulatory diseases (MRR, 2.3; 95% CI, 1.2-4.2) was significantly higher among nonparticipants than among participants. Standardized mortality ratio for the studied outcomes tended to be increased among nonparticipants and was generally decreased among participants.

CONCLUSION

Individuals who might benefit most from screening are overrepresented among nonparticipants. This self-selection may attenuate the cost-effectiveness of screening programs on a population level.

Self-reported adverse events after groin hernia repair, a study based on a national register

OBJECTIVES

In most clinics, follow-up after inguinal hernia surgery is not a routine procedure and complications may pass unnoticed, thus impairing quality assessment. The aim of this study was to investigate the frequency, spectrum, and risk factors of short-term adverse events after groin hernia repair.

METHODS

All patients aged 15 years or older with a primary unilateral inguinal or femoral hernia repair recorded in the Swedish Hernia Register (SHR) between November 1 and December 31, 2002 were sent a questionnaire asking about complications within the first 30 postoperative days.

RESULTS

Of the 1643 recorded patients, 1448 (88.1%) responded: 1341 (92.6%) were men and 107 (7.4%) women, mean age 59 years. There were 195 (11.9%) nonresponders. Postoperative complications reported in the questionnaire were hematoma in 203 (14.0%) patients, severe pain in 168 (11.6%), testicular pain in 120 (8.3%), and infection in 105 (7.3%). Adverse events were reported in the questionnaire by 391 (23.8%) patients, whereas only 85 (5.2%) were affected according to the SHR. Risk factors for postoperative complications were age below the median (59 years) among the studied hernia patients (OR 1.36; 95% CI 1.06-1.74) and laparoscopic repair (OR 2.66; 95% CI 1.17-6.05).

CONCLUSION

Questionnaires provide valuable additional information concerning postoperative complications. We recommend that they become an integrated part of routine postoperative assessment.

Risks of nontraumatic lower-extremity amputations in patients with type 1 diabetes: a population-based cohort study in Sweden

OBJECTIVE

The purpose of this study was to estimate the risks of nontraumatic lower-extremity amputations (LEAs) in patients with type 1 diabetes.

RESEARCH DESIGN AND METHODS

We identified 31,354 patients with type 1 diabetes (15,001 women and 16,353 men) in the Swedish Inpatient Register between 1975 and 2004. The incidence of nontraumatic LEAs was followed up until 31 December 2004 by cross-linkage in the Inpatient Register and linkage to the Death and Migration registers. Poisson regression modeling was used to compare the risks of nontraumatic LEAs during different calendar periods of follow-up, with adjustment for both sex and attained age at follow-up. Standardized incidence ratios (SIRs) were used to estimate the relative risks (RRs) with the age-, sex-, and calendar period-matched general Swedish population as reference. The cumulative probability of nontraumatic LEAs was calculated by the Kaplan-Meier method.

RESULTS

In total, 465 patients with type 1 diabetes underwent nontraumatic LEAs. The risk was lower during the most recent calendar period (2000-2004) than during the period before 2000 (RR 0.6 [95% CI 0.5-0.8]). However, even in this most recent period, the risk for nontraumatic LEAs among these relatively young patients was 86-fold higher than that in the matched general population (SIR 85.8 [72.9-100.3]). By age 65 years, the cumulative probability of having a nontraumatic LEA was 11.0% for women with type 1 diabetes and 20.7% for men with type 1 diabetes.

CONCLUSIONS

Although the risks appeared to have declined in recent years, patients with type 1 diabetes still have a very high risk for nontraumatic LEAs.

Survival after blood transfusion

BACKGROUND

Long-term survival of transfusion recipients has rarely been studied. This study examines short- and long-term mortality among transfusion recipients and reports these as absolute rates and rates relative to the general population.

STUDY DESIGN AND METHODS

Population-based cohort study of transfusion recipients in Denmark and Sweden followed for up to 20 years after their first blood transfusion. Main outcome measure was all-cause mortality.

RESULTS

A total of 1,118,261 transfusion recipients were identified, of whom 62.0 percent were aged 65 years or older at the time of their first registered transfusion. Three months after the first transfusion, 84.3 percent of recipients were alive. One-, 5-, and 20-year posttransfusion survival was 73.7, 53.4, and 27.0 percent, respectively. Survival was slightly poorer in men than in women, decreased with increasing age, and was worst for recipients transfused at departments of internal medicine. The first 3 months after the first transfusion, the standardized mortality ratio (SMR) was 17.6 times higher in transfusion recipients than in the general population. One to 4 years after first transfusion, the SMR was 2.1 and even after 17 years the SMR remained significantly 1.3-fold increased.

CONCLUSION

The survival and relative mortality patterns among blood transfusion recipients were characterized with unprecedented detail and precision. Our results are relevant to assessments of the consequences of possible transfusion-transmitted disease as well as for cost-benefit estimation of new blood safety interventions.

DNA repair polymorphisms and the risk of stomach adenocarcinoma and severe chronic gastritis in the EPIC-EURGAST study

BACKGROUND

The contribution of genetic variation in DNA repair genes to gastric cancer (GC) risk remains essentially unknown. The aim of this study was to explore the relative contribution of DNA repair gene polymorphisms to GC risk and severe chronic atrophic gastritis (SCAG). Method A nested case control study within the EPIC cohort was performed including 246 gastric adenocarcinomas and 1175 matched controls. Controls with SCAG (n = 91), as defined by low pepsinogen A (PGA) levels, and controls with no SCAG (n = 1061) were also compared. Twelve polymorphisms at DNA repair genes (MSH2, MLH1, XRCC1, OGG1 and ERCC2) and TP53 gene were analysed. Antibodies against Helicobacter pylori were measured.

RESULTS

No association was observed for any of these polymorphisms with stomach cancer risk. However, ERCC2 K751Q polymorphism was associated with an increased risk for non-cardial neoplasm [odds ratio (OR) = 1.78; 95% confidence interval (CI) 1.02-3.12], being ERCC2 K751Q and D312N polymorphisms associated with the diffuse type. ERCC2 D312N (OR = 2.0; 95% CI 1.09-3.65) and K751Q alleles (OR = 1.82; 95% CI 1.01-3.30) and XRCC1 R399Q (OR = 1.69; 95% CI 1.02-2.79) allele were associated with an increased risk for SCAG.

CONCLUSION

Our study supports a role of ERCC2 in non-cardial GC but not in cardial cancer. A concordant result was observed for subjects with low PGA levels. XRCC1 allele was associated also with SCAG. This is the first prospective study suggesting that individual variation in DNA repair may be relevant for gastric carcinogenesis, a finding that will require further confirmation validation in larger independent studies.

Risk of gastroesophageal cancer among smokers and users of Scandinavian moist snuff

Although Scandinavian moist snuff ("snus"), no doubt, is a safer alternative to smoking, there is limited evidence against an association with gastroesophageal cancers. In a retrospective cohort study, we investigated esophageal and stomach cancer incidence among 336,381 male Swedish construction workers who provided information on tobacco smoking and snus habits within a health surveillance program between 1971 and 1993. Essentially complete follow-up through 2004 was accomplished through linkage to several nationwide registers. Multivariable Cox proportional hazards regression models estimated relative risks (RR) and 95% confidence intervals (CIs). Compared to never-users of any tobacco, smokers had increased risks for adenocarcinoma (RR = 2.3, 95% CI 1.4-3.7) and squamous cell carcinoma (RR = 5.2, 95% CI 3.1-8.6) of the esophagus, as well as cardia (RR = 2.1, 95% CI 1.5-3.0) and noncardia stomach (RR = 1.3, 95% CI 1.2-1.6) cancers. We also observed excess risks for esophageal squamous cell carcinoma (RR = 3.5, 95% CI 1.6-7.6) and noncardia stomach cancer (RR = 1.4, 95% CI 1.1-1.9) among snus users who had never smoked. Although confounding by unmeasured exposures, and some differential misclassification of smoking, might have inflated the associations, our study provides suggestive evidence for an independent carcinogenic effect of snus.

Improving health profile of blood donors as a consequence of transfusion safety efforts

BACKGROUND

Transfusion safety rests heavily on the health of blood donors. Although they are perceived as being healthier than average, little is known about their long-term disease patterns and to which extent the blood banks' continuous efforts to optimize donor selection has resulted in improvements. Mortality and cancer incidence among blood donors in Sweden and Denmark was investigated.

STUDY DESIGN AND METHODS

All computerized blood bank databases were compiled into one database, which was linked to national population and health data registers. With a retrospective cohort study design, 1,110,329 blood donors were followed for up to 35 years from first computer-registered blood donation to death, emigration, or December 31, 2002. Standardized mortality and incidence ratios expressed relative risk of death and cancer comparing blood donors to the general population.

RESULTS

Blood donors had an overall mortality 30 percent lower (99% confidence interval [CI] 29%-31%) and cancer incidence 4 percent lower (99% CI 2%-5%) than the background population. Mortality rates and cancer incidence were lowest for outcomes that are recognized as being related to lifestyle factors such as smoking or to the selection criteria for blood donation. Blood donors recruited in more recent years exhibited a lower relative mortality than those who started earlier.

CONCLUSION

Blood donors enjoy better than average health. Explicit and informal requirements for blood donation in Scandinavia, although mostly of a simple nature, have successfully refined the selection of a particularly healthy subpopulation.

Macrolide resistance in the normal microbiota after Helicobacter pylori treatment

Large-scale chemoprevention of peptic ulcer disease and gastric cancer through eradication of Helicobacter pylori would expose large population groups to antibiotics, which raises concerns about possible dissemination of antibiotic resistance. The objective of this cohort study was to determine whether a triple therapy, containing omeprazole, clarithromycin, and metronidazole, of H. pylori infection increases the prevalence of macrolide resistance in the normal microbiota. 85 patients with a peptic ulcer disease with verified H. pylori infection and 12 dyspeptic patients without positive findings upon endoscopy were included. Minimal inhibitory concentrations of clarithromycin for Staphylococcus, Streptococcus, Enterococcus and Bacteroides spp. were determined from samples taken before and after treatment, and 1 y later. Before treatment, macrolide resistance was observed in 11%, 31%, 9% and 11% of the staphylococci, streptococci, enterococci and Bacteroides, respectively. The number of resistant isolates remained elevated after 1 y, most notably for staphylococci and streptococci. No development of persistent resistance was detected in the untreated control group. Triple therapy including clarithromycin leads to persistent macrolide resistance in the normal microbiota. A prevalent pool of resistance genes in the normal microbiota constitutes an ecological hazard that needs to be considered before global treatment programmes for eradication of H. pylori are implemented.

Cancer incidence in blood transfusion recipients

BACKGROUND

Blood transfusions may influence the recipients' cancer risks both through transmission of biologic agents and by modulation of the immune system. However, cancer occurrence in transfusion recipients remains poorly characterized.

METHODS

We used computerized files from Scandinavian blood banks to identify a cohort of 888,843 cancer-free recipients transfused after 1968. The recipients were followed from first registered transfusion until the date of death, emigration, cancer diagnosis, or December 31, 2002, whichever came first. Relative risks were expressed as ratios of the observed to the expected numbers of cancers, that is, standardized incidence ratios (SIRs), using incidence rates for the general Danish and Swedish populations as a reference. All statistical tests were two-sided.

RESULTS

During 5,652,918 person-years of follow-up, 80,990 cancers occurred in the transfusion recipients, corresponding to a SIR of 1.45 (95% confidence interval [CI] = 1.44 to 1.46). The SIR for cancer overall decreased from 5.36 (95% CI = 5.29 to 5.43) during the first 6 months after transfusion to 1.10 or less for follow-up periods more than 2 years after the transfusion. However, the standardized incidence ratios for cancers of the tongue, mouth, pharynx, esophagus, liver, and respiratory and urinary tracts and for squamous cell skin carcinoma remained elevated beyond 10 years after the transfusion.

CONCLUSIONS

The marked increase in cancer risk shortly after a blood transfusion may reflect the presence of undiagnosed occult cancers with symptoms that necessitated the blood transfusion. The continued increased risk of tobacco- and alcohol-related cancers suggests that lifestyle and other risk factors related to conditions prompting transfusion rather than transfusion-related exposures per se are important to the observed cancer occurrence in the recipients.

Diagnosing Barrett's oesophagus: factors related to agreement between endoscopy and histology

BACKGROUND AND STUDY AIM

Few previous studies have addressed the agreement between endoscopy and histology regarding Barrett's oesophagus in unselected endoscopy patients. Our aim was to quantify this agreement, and to study its relation to clinical and endoscopic characteristics in consecutive patients coming for first-time gastroscopy.

METHODS

We invited consecutive patients aged 18-79 years and endoscoped for the first time at endoscopy units exclusively serving defined catchment areas in southeast Sweden. Endoscopic and clinical data were recorded according to a predetermined protocol, and biopsies were taken from the distal oesophagus in all patients.

RESULTS

Among 705 patients included, 17% [95% confidence interval (CI): 14-20] had endoscopically visible columnar mucosa above the oesophagogastric junction and 38% (95% CI: 34-42) had columnar mucosa in at least one biopsy irrespective of the endoscopic finding. The overall concordance between endoscopy and histology regarding presence (or absence) of columnar mucosa above the oesophagogastric junction was 74% (95% CI: 71-77) and the agreement beyond chance, as measured by Kappa (kappa) statistics, was fair, kappa=0.38 (95% CI: 0.32-0.45). The agreement between the endoscopic assessment and intestinal metaplasia at biopsy was 86% (95% CI: 83-88), but kappa was only 0.31 (95% CI: 0.21-0.41). Our data were consistent with a lower threshold for macroscopic detection of columnar epithelium above the oesophagogastric junction, when risk factors for Barrett's oesophagus were present.

CONCLUSION

The agreement between macroscopic and microscopic assessments of Barrett's oesophagus is no more than fair, and partly dependent on the presence of patient characteristics suggestive of pathology in this region.

Fertility in women with type 1 diabetes: a population-based cohort study in Sweden

OBJECTIVE

The purpose of this study was to assess fertility in women with type 1 diabetes and the risk of congenital malformations in their offspring.

RESEARCH DESIGN AND METHODS

This was a register-based cohort study in Sweden. All 5,978 women hospitalized for type 1 diabetes at age <or=16 years identified in the Swedish Inpatient Register during 1965-2004 were followed until the end of 2004 through linkage to nationwide registers. A standardized fertility ratio (SFR), the ratio of observed to expected number of live births, with 95% CIs, was used to express the relative fertility rate. The proportion of newborns with congenital malformations was compared with that of the general population.

RESULTS

We observed 4,013 live births (SFR 0.80 [95% CI 0.77-0.82]). The SFRs for those who had retinopathy, nephropathy, neuropathy, or cardiovascular complications were 0.63, 0.54, 0.50, and 0.34, respectively. Stratified analyses by year of first hospitalization showed that the reduced fertility was confined to women first hospitalized before 1985, but the presence of complications was associated with subfertility in all calendar-year strata. The proportions of newborns with congenital malformations decreased from 11.7% during 1973-1984 to 6.9% during 1995-2004 but were consistently higher than the corresponding figures for the general population.

CONCLUSIONS

Women with type 1 diabetes have reduced fertility, but it appears that normalization has occurred among women with uncomplicated disease and an onset in the past 20 years. Our results suggest that the stricter metabolic control exercised in the past 20 years may have helped prevent subfertility. However, although the risk of congenital malformations has decreased, it is still higher than that for the general population.

Oral use of Swedish moist snuff (snus) and risk for cancer of the mouth, lung, and pancreas in male construction workers: a retrospective cohort study

BACKGROUND

Although classified as carcinogenic, snuff is used increasingly in several populations. Scandinavian moist snuff (snus) has been proposed as a less harmful alternative to smoking, but precise data on the independent associations of snus use with site-specific cancers are sparse. We aimed to assess the risks for cancer of the oral cavity, lung, and pancreas.

METHODS

Detailed information about tobacco smoking and snus use was obtained from 279 897 male Swedish construction workers in 1978-92. Complete follow-up until end of 2004 was accomplished through links with population and health registers. To distinguish possible effects of snus from those of smoking, we focused on 125 576 workers who were reported to be never-smokers at entry. Adjusted relative risks were derived from Cox proportional hazards regression models.

FINDINGS

60 cases of oral, 154 of lung, and 83 of pancreatic cancer were recorded in never-smokers. Snus use was independently associated with increased risk of pancreatic cancer (relative risk for ever-users of snus 2.0; 95% CI 1.2-3.3, compared with never-users of any tobacco), but was unrelated to incidence of oral (0.8, 95% CI 0.4-1.7) and lung cancer (0.8, 0.5-1.3).

INTERPRETATION

Use of Swedish snus should be added to the list of tentative risk factors for pancreatic cancer. We were unable to confirm any excess of oral or lung cancer in snus users.

Long-term risk of gastric cancer by subsite in operated and unoperated patients hospitalized for peptic ulcer

OBJECTIVE

We aimed to investigate whether the elevated risk of gastric cancer among patients with gastric ulcer (GU) and the enigmatic low risk among patients with duodenal ulcer (DU) pertain to both cardia and noncardia cancer. We also studied the risks among operated patients while taking the disparate baseline risks into consideration.

METHODS

Retrospective cohorts of 59,550 and 79,412 unoperated patients with DU and GU, respectively, plus 12,840 patients with partial gastric resection and 8,105 with vagotomy, recorded in the Swedish Inpatient Register since 1970, were followed from the first hospitalization (date of operation for the surgery cohort) until occurrence of any cancer, death, emigration, definitive surgery, or December 31, 2003. Standardized incidence ratios (SIRs) with 95% confidence intervals (CIs) expressed relative risk (RR), compared to the age-, sex-, and calendar period-matched Swedish population. Cox regression produced adjusted RR estimates among operated patients, relative to unoperated ones with the same ulcer type.

RESULTS

While unoperated DU patients had a halved risk of noncardia cancer (SIR=0.5, 95% CI 0.4-0.7), their risk of cardia cancer was slightly above expectation (SIR=1.2, 95% CI 0.8-1.7). Unoperated GU patients had doubled risks for both cancers (SIR=2.1, 95% CI 2.0-2.4 and SIR=1.9, 95% CI 1.4-2.3, respectively). DU patients who underwent gastric resection had a 60% risk elevation (RR=1.6, 95% CI 1.0-2.5) compared to unoperated ones. Vagotomy was associated with a greater risk in the first 10 yr, but this excess disappeared with further follow-up. Resected GU patients had a 40% risk reduction relative to their unoperated peers (RR=0.6, 95% CI 0.5-0.8). This reduction persisted well beyond the first postoperative decade.

CONCLUSION

The DU-related protection against gastric cancer does not seem to pertain to cardia cancer. With gastric resection, risks are shifted toward normality, regardless of underlying ulcer type.

Risk for gastric cancer after cholecystectomy

BACKGROUND

It is becoming increasingly evident that chronic inflammation may predispose cancer development. In the stomach, inflammation caused by Helicobacter pylori infection is linked to gastric cancer. Cholecystectomy is regularly followed by duodenogastric bile reflux and reactive gastritis. To test whether a noninfectious long-standing inflammation impels gastric carcinogenesis as well, we assessed the risk of gastric cancer in a large, population-based cohort of cholecystectomized patients.

METHODS

We identified 251,672 individuals, in the Swedish National Inpatient Register, who had undergone cholecystectomy between 1970 and 1997. All incident cases of gastric cancer were identified through linkage to the Swedish Cancer Registry. Standardized incidence ratios (SIRs) were calculated for comparisons with cancer rates of the general population in Sweden.

RESULTS

We found an 11% greater overall risk of distal gastric cancer (SIR=1.11, 95% CI 1.04-1.19). The risk increase was only observed among men (SIR=1.21, 95% CI 1.10-1.32), whereas no excess risk was evident for women. For men, the risk was elevated for up to 10 yr after surgery, but this elevation disappeared with longer follow-up time. There was no clear association between cholecystectomy and cardia cancer (SIR=0.95, 95% CI 0.76-1.16).

CONCLUSIONS

Inconsistency over gender strata, implausibly short induction and latency time, and disappearance of the effect over time makes a causal relationship between cholecystectomy and distal gastric cancer less likely. The findings set aside concerns of harmful long-term consequences of cholecystectomy.

Risk of cancer after blood transfusion from donors with subclinical cancer: a retrospective cohort study

BACKGROUND

Although mechanisms for detection of short-term complications after blood transfusions are well developed, complications with delayed onset, notably transmission of chronic diseases such as cancer, have been difficult to assess. Our aim was to investigate the possible risk of cancer transmission from blood donors to recipients through blood transfusion.

METHODS

We did a register-based retrospective cohort study of cancer incidence among patients who received blood from donors deemed to have a subclinical cancer at the time of donation. These precancerous donors were diagnosed with a cancer within 5 years of the donation. Data from all computerised blood bank registers in Sweden and Denmark gathered between 1968 and 2002 were merged into a common database. Demographic and medical data, including mortality and cancer incidence, were ascertained through linkages with nationwide, and essentially complete, population and health-care registers. The risk of cancer in exposed recipients relative to that in recipients who received blood from non-cancerous donors was estimated with multivariate Poisson regression, adjusting for potential confounding factors.

FINDINGS

Of the 354 094 transfusion recipients eligible for this analysis, 12,012 (3%) were exposed to blood products from precancerous donors. There was no excess risk of cancer overall (adjusted relative risk 1.00, 95% CI 0.94-1.07) or in crude anatomical subsites among recipients of blood from precancerous donors compared with recipients of blood from non-cancerous donors.

INTERPRETATION

Our data provide no evidence that blood transfusions from precancerous blood donors are associated with increased risk of cancer among recipients compared with transfusions from non-cancerous donors.

Validity and reliability of self-reported total energy expenditure using a novel instrument

Improved methods for quantitative self-reports of total physical activity in epidemiological studies are needed. We evaluated randomly selected individuals' ability to integrate their perception of physical activity over time to produce an estimate of the "usual" level, using a novel instrument for self-quantification of energy expenditure. A population-based sample of 418 Swedish men and women, age 20-59, completed a questionnaire containing the new instrument. For validation, three 24 hour recalls by phone served as gold standard. Reproducibility was assessed through administering the instrument another three times. The validation involved 133 subjects and another 160 completed the reproducibility evaluation. Pearson correlation between usual daily energy expenditure measured by the instrument and the mean of the 24 hour recalls was 0.73. After subdividing the self-reported daily energy expenditure and the mean of the 24 hour recalls into quintiles, 83.5% of the participants remained in the same quintile, or one quintile apart. There was a tendency towards overestimation of usual daily physical activity. This was significantly associated with low education. Reproducibility showed an intraclass correlation of 0.55. Although integrated reports of usual daily energy expenditure over longer periods seem to be afflicted with a tendency of overestimation, total energy expenditure can be estimated with reasonable validity and reproducibility using our instrument.

CagA+ Helicobacter pylori infection and gastric cancer risk in the EPIC-EURGAST study

Helicobacter pylori (H. pylori), atrophic gastritis, dietary and life-style factors have been associated with gastric cancer (GC). These factors have been evaluated in a large case-control study nested in the European Prospective Investigation into Cancer and Nutrition carried out in 9 countries, including the Mediterranean area. Participants, enrolled in 1992-1998, provided life-style and dietary information and a blood sample (360,000; mean follow-up: 6.1 years). For 233 GC cases diagnosed after enrolment and their 910 controls individually-matched by center, gender, age and blood donation date H. pylori antibodies (antilysate and antiCagA) and plasma Pepsinogen A (PGA) were measured by ELISA methods. Severe chronic atrophic gastritis (SCAG) was defined as PGA circulating levels <22 microg/l. Overall, in a conditional logistic regression analysis adjusted for education, smoke, weight and consumption of total vegetables, fruit, red and preserved meat, H. pylori seropositivity was associated with GC risk. Subjects showing only antibodies anti-H. pylori lysate, however, were not at increased risk, while those with antiCagA antibodies had a 3.4-fold increased risk. Overall, the odds ratio associated with SCAG was 3.3 (95% CI 2.2-5.2). According to site, the risk of noncardia GC associated with CagA seropositivity showed a further increase (OR 6.5; 95% CI 3.3-12.6); on the other hand, a ten-fold increased risk of cardia GC was associated with SCAG (OR 11.0; 95% CI 3.0-40.9). These results support the causal relationship between H. pylori CagA+ strains infection, and GC in these European populations even after taking into account dietary habits. This association was limited to distal GC, while serologically defined SCAG was strongly associated with cardia GC, thus suggesting a divergent risk pattern for these 2 sites.