Showing papers by "Olof Nyrén published in 2000"

The role of tobacco, snuff and alcohol use in the aetiology of cancer of the oesophagus and gastric cardia

Abstract: While tobacco and alcohol are established risk factors for oesophageal squamous-cell carcinoma, their roles in the aetiology of the increasingly common oesophageal adenocarcinoma remains uncertain. We tested the association between tobacco, snuff and alcohol use and the risk of oesophageal and cardia cancer in a nationwide, population-based case-control study in Sweden. Face-to-face interviews were conducted with 618 (81% of all eligible) patients (189 oesophageal adenocarcinoma, 262 cardia adenocarcinoma and 167 oesophageal squamous-cell carcinoma) and 820 control subjects. Odds ratios (OR) were calculated by logistic regression with multivariate adjustments for potential confounding. The risk of oesophageal adenocarcinoma was not associated with snuff or alcohol use, and the association with smoking was weak or absent. Gastric cardia adenocarcinoma was dose-dependently associated with smoking (OR=4.2, 95% CI=2.5-7.0 among heavy smokers compared with never-smokers), but not with alcohol or snuff use. Oesophageal squamous-cell carcinoma was strongly associated with tobacco, moderately with alcohol, but not with snuff use; combined use of tobacco and alcohol entailed a strongly increased risk (OR=23.1, 95% CI=9.6-56.0 among heavy users compared with never-users). We conclude that tobacco smoking, a strong risk factor for oesophageal squamous-cell carcinoma and cardia adenocarcinoma, does not play an important role in the aetiology of oesophageal adenocarcinoma. None of the studied exposures can explain the increasing incidence of oesophageal adenocarcinoma.

No relation between body mass and gastro-oesophageal reflux symptoms in a Swedish population based study

Abstract: BACKGROUND There is a widespread notion that obesity leads to gastro-oesophageal reflux but scientific evidence of an association is limited and inconsistent. AIMS To estimate the strength of the association between body mass and reflux symptoms, we performed a population based cross sectional interview study. SUBJECTS Population based, randomly selected, middle aged or elderly persons in Sweden in 1995–1997. METHODS At face-to-face interviews we asked a stratified sample of Swedes about body measures and occurrence of reflux symptoms. Odds ratios (OR) with 95% confidence intervals (CI), calculated by logistic regression with multivariate adjustments for covariates, were the measures of association. RESULTS Reflux symptoms occurring at least once a week more than five years before the interview were reported by 135 (16%) of the 820 interviewees. Among those who had ever been overweight during adulthood (body mass index (BMI) ⩾25 kg/m 2 ), the OR of having recurrent reflux symptoms was 0.99 (95% CI 0.66–1.47) compared with those who were never overweight. There was no association between BMI at age 20, BMI 20 years before the interview, or maximum adult BMI and occurrence of reflux symptoms: ORs per unit increase in BMI were 1.00 (95% CI 0.93–1.09), 1.03 (95% CI 0.96–1.10), and 1.01 (95% CI=0.95 1.07), respectively. There was no association between BMI and severity or duration of reflux symptoms. CONCLUSIONS Gastro-oesophageal reflux symptoms occur independently of body mass index. Weight reduction may not be justifiable as an antireflux therapy.

Association between Medications That Relax the Lower Esophageal Sphincter and Risk for Esophageal Adenocarcinoma

Abstract: The use of lower esophageal sphincter–relaxing medications was associated with increased risk for esophageal adenocarcinoma.

Antioxidants and cancers of the esophagus and gastric cardia.

Abstract: Antioxidant vitamins have attracted considerable attention in previous studies of esophageal squamous-cell carcinoma, but dietary studies of adenocarcinoma of the esophagus and gastric cardia remain sparse. Treating these tumors as distinct diseases, we studied intakes of vitamin C, beta-carotene and alpha-tocopherol in a nationwide population-based case-control study in Sweden, with 185, 165, and 258 cases of esophageal adenocarcinoma, esophageal squamous-cell carcinoma, and gastric cardia adenocarcinoma, respectively, and 815 controls. Subjects with a high parallel intake of vitamin C, beta-carotene, and alpha-tocopherol showed a 40-50% decreased risk of both histological types of esophageal cancer compared with subjects with a low parallel intake. Antioxidant intake was not associated with the risk of gastric cardia adenocarcinoma. Separately, vitamin C and beta-carotene reduced the risk of esophageal cancers more than alpha-tocopherol. We found that antioxidant intake is associated with similar risk reductions for both main histological types of esophageal cancer. Our findings indicate that antioxidants do not explain the diverging incidence rates of the 2 histological types of esophageal cancer. Moreover, our data suggest that inverse associations with esophageal squamous-cell carcinoma and adenocarcinoma may be stronger among subjects under presumed higher oxidative stress due to smoking or gastroesophageal reflux, respectively. Our results may be relevant for the implementation of focused, cost-effective preventive measures.

Dietary antioxidant intake and the risk of cardia cancer and noncardia cancer of the intestinal and diffuse types: a population-based case-control study in Sweden

Abstract: In spite of diverging incidence trends, subsite, and subtype-specific gastric cancer data on the association with dietary antioxidants are sparse. We aimed to test whether the apparent protective effect of antioxidants is mainly confined to noncardia (distal) cancer of the intestinal subtype, to which most of the incidence decline in gastric cancer has been ascribed. In a Swedish study base (total population 1.3 million), we interviewed 567 cases uniformly classified to subsite (cardia vs. noncardia) and subtype (intestinal vs. diffuse), and 1165 population-based controls, frequency matched for age and sex. Serologic data on H. pylori status was available for a subset of 542 individuals. Ascorbic acid (vitamin C) was inversely associated with all subsites and subtypes of gastric cancer in a significant dose-response manner (all p<0.05), with risk reductions between 40% and 60%. beta-carotene was also strongly and negatively associated with risk, particularly with the intestinal type. The associations with alpha-tocopherol (vitamin E) were less clear. The highest parallel intake of all three antioxidants (quartiles 4), compared to those with the lowest parallel intakes (quartiles 1), was associated with a 70% lower risk of developing noncardia cancer (OR 0.3, 95% CI 0.1-0.9). Our results suggest that antioxidants might be especially beneficial among subjects at increased risk for gastric cancer such as smokers and those infected by H. pylori. We conclude that a high intake of antioxidants, as a consequence of high consumption of fruit and vegetables, may lower the risk not only for gastric cancer of the intestinal type, but also for diffuse type adenocarcinoma and cardia cancer.

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

Abstract: 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.

Decreasing incidence of both major histologic subtypes of gastric adenocarcinoma--a population-based study in Sweden.

Abstract: While the overall incidence of gastric cancer has fallen, presumably to a large extent in parallel with Helicobacter pylori infection, the occurrence of the diffuse histologic type is thought to have remained more stable, questioning the aetiologic role of H. pylori. We have analysed the incidence of the intestinal and diffuse types separately, while considering subsite (cardia/non-cardia). With an extensive prospective effort we identified all incident cases of gastric adenocarcinoma (n = 1337) in a well-defined Swedish population (1.3 million) 1989–1994. Tumours were uniformly classified histologically and topographically. Subgroup-specific incidence rates were computed and modelled using multivariate logistic regression. Site-specific trends were clearly discrepant. The overall incidence of adenocarcinoma distal to the gastric cardia declined by 9% (95% confidence interval 6–12%) per year, while cardia cancer remained stable. Thus, the feared rise in cardia cancer could not be confirmed despite clear site-specific trend discrepancies. The intestinal type predominated, especially in high-risk areas, while diffuse tumours prevailed among young patients and women. Both main histologic types of gastric adenocarcinoma declined markedly, at similar rapidity, and with no significant trend differences between the intestinal and diffuse types, even after multivariate adjustments. Our results are consistent with an aetiologic role of environmental factors including H. pylori also for diffuse-type gastric cancers. © 2000 Cancer Research Campaign

Breast cancer risk and lifetime leisure-time and occupational physical activity (Sweden).

Abstract: Objective: To clarify whether type and timing of physical activity affect postmenopausal breast cancer risk. Methods: In a population-based case–control study within the Swedish female population 50–74 years of age, 3347 women with invasive, postmenopausal breast cancer (84% of all eligible) and 3455 controls (82% of all selected) reported on past leisure-time physical activity. Record linkage to decennial census data (1960–1990) provided estimates of their occupational physical activity. Odds ratios with 95% confidence intervals were estimated by multivariate logistic regression. Results: After adjustment for potential confounders, women in sedentary occupations during their reproductive years (25–44 years of age) had a 50% higher risk for postmenopausal breast cancer, compared to those with the physically most demanding jobs. Only the most recent leisure-time physical activity was associated with a significant risk reduction. Women with the combination of sedentary jobs and lack of leisure-time exercise had a three-fold higher risk of breast cancer, compared to the physically most active both inside and outside the workplace. Conclusion: Effects of occupational and leisure-time physical activity on breast cancer risk appear to have different latency times, and/or to be effect-modified by age or reproductive status. Although chance might explain our findings, it is advisable to consider type and timing of physical activity in future studies.

Breast cancer following breast reduction surgery in Sweden.

Abstract: Women undergoing breast reduction surgery have been reported to be at low subsequent risk of breast cancer, especially when the surgery is performed after age 40. To evaluate the age and time-related patterns of cancer risk following surgical removal of breast tissue, we identified 31,910 women who

Heredity and risk of cancer of the esophagus and gastric cardia.

Abstract: The importance of genetic factors in the etiology of esophageal cancer is uncertain. We addressed the question of heredity in a population-based, nationwide case-control study conducted in Sweden during 1995 through 1997. The study involved 189 patients with esophageal adenocarcinoma, 262 with cardia adenocarcinoma, 167 with esophageal squamous cell carcinoma, and, for comparison, 820 control subjects. Familial occurrence of cancer was explored at face-to-face interviews. Logistic regression, with multivariate adjustment for potential confounders, was used to calculate odds ratios (ORs), which estimated relative risk. Occurrence of esophageal cancer among first-degree relatives did not increase the risk of adenocarcinoma or squamous cell carcinoma of the esophagus. Neither were there any significant associations with familial occurrence of gastric cancer or other gastrointestinal tumors. The risk of cardia adenocarcinoma was moderately increased among persons with first-degree relatives with gastric cancer (OR, 1.6; 95% confidence interval, 1.0-2.6). Familial occurrence of any cancer was not associated with increased risks of any of the three studied tumors. In conclusion, heredity does not seem to contribute importantly to the occurrence of esophageal cancer of any histological type. A weak association between familial gastric cancer and the risk of cardia cancer may represent a genetic link.

Characteristics of women with cosmetic breast augmentation surgery compared with breast reduction surgery patients and women in the general population of Sweden.

Abstract: To determine whether women with cosmetic breast implants have distinct demographic, lifestyle, and reproductive characteristics that put them at increased risk for subsequent morbidity, the authors compared 1,369 such women to 2,211 women who had undergone breast reduction surgery, and to a random sample of 49,262 women from the general population of Sweden. Information was collected through self-administered questionnaires, and comparisons were made using the prevalence odds ratio. Women with cosmetic breast implants were significantly (p <0.05) more likely to be current smokers, have a lower body mass index, have had a prematurely terminated pregnancy (induced abortion or miscarriage), and have had fewer live births than either women who underwent breast reduction or women from the general population. Type of implant (silicone gel or saline) did not modify the associations. Regardless of the comparison group used, studies of the health effects of breast implants need to consider that women who undergo cosmetic breast implantation have certain distinct characteristics.

Physical activity and postmenopausal endometrial cancer risk (Sweden)

Abstract: Objectives:To examine the hypothesis that sedentary women have an increased risk of endometrial cancer compared to physically active women. Methods:This is a population-based case–control study in the entire Swedish female population aged 50–74 years in 1994–1995. We obtained self-reported information on leisure-time physical activity during childhood, at ages 18–30, and recently from 709 incident case women with endometrial cancer and 3368 population controls. Occupational physical activity was estimated through record linkage to the Swedish census data from 1960, 1970, 1980, and 1990. Odds ratios (OR) and 95% confidence intervals (CI) were calculated for different activity levels by multivariate logistic regression, taking into account potential confounders. Results:Comparing lowest to highest (reference) levels of physical exercise, we observed statistically significant associations with risk of endometrial cancer for leisure-time activity at age 18–30 years (multivariate OR = 1.4; 95% CI = 1.0–1.8; p for trend 0.01) and in recent years (multivariate OR=1.3; 95% CI = 1.0–1.7; p for trend 0.01). We found similar associations comparing lowest to highest (reference) levels of occupational activity assessed at the censuses in 1980 (multivariate OR = 1.4; 95% CI = 1.0–1.9; p for trend 0.03) and 1990 (multivariate OR = 1.3; 95% CI = 0.9–1.9, p for trend 0.05), but a less consistent association with censuses in 1960 and 1970. The increased risk associated with low level of occupational physical activity was confined to women who were not obese and to women who were smokers. Conclusion:Our data, in conjunction with past epidemiological studies, indicate that both occupational and leisure-time physical activity may reduce the risk for postmenopausal endometrial cancer.

Surgery for Stomach Cancer in a Defined Swedish Population: Current Practices and Operative Results

Abstract: Objective: To study routine surgical in-hospital care, and to relate postoperative morbidity and mortality to age, sex, tumour stage, operation done, and surgical workload of the hospital. Design: Prospective population-based study. Setting: All hospitals that diagnosed new cases of stomach cancer in five counties in central and northern Sweden, 1 February 1989-31 January 1995. Patients: All 1024 patients diagnosed as having a new adenocarcinoma of the stomach. Results: The stomach cancer was in such an advanced stage at diagnosis that only half of the patients could be offered a potentially curative operation. The tumour was resectable in 632 patients (62%). Distal gastric resection was done for 359 (57%) and total gastrectomy in 259 (41%) of all the resected cases. Postoperative complications occurred in 250 patients (31%). In multivariate analyses the relative risk (RR) for postoperative complications increased to 2.3 (95% confidence interval [CI] = 1.3 to 4.3) in patients over 79 years of age compared...

Alcohol and breast cancer risk: the alcoholism paradox.

Abstract: A population-based cohort study of 36 856 women diagnosed with alcoholism in Sweden between 1965 and 1995 found that alcoholic women had only a small 15% increase in breast-cancer incidence compared to the general female population. It is therefore apparent, contrary to expectation, that alcoholism does not increase breast-cancer risk in proportion to presumed ethanol intake.

Risk for gastric cancer after antibiotic prophylaxis in patients undergoing hip replacement.

Abstract: Despite strong evidence of an association between Helicobacter pylori and gastric cancer, the benefit of eradicating H. pylori infection is unknown. Our aim was to test the hypothesis that exposure to high doses of antibiotics reduces risk for gastric cancer via possible eradication of H. pylori We conducted a nationwide case-control study nested in a cohort of 39,154 patients who underwent hip replacement surgery between 1965 and 1983. Such patients frequently receive prophylactic antibiotic treatment. During follow-up through 1989, we identified 189 incident cases of gastric cancer. For each case, three controls were selected from the cohort. Exposure data were abstracted from hospital records. Blood samples from a separate cohort undergoing hip replacement surgery were analyzed for anti-H. pylori IgG before and after surgery. Both long-term antibiotic treatment before surgery [odds ratio (OR), 0.3; 95% confidence interval (CI), 0.1-0.7] and prophylactic antibiotic treatment (OR, 0.7; 95% CI, 0.5-1.1) conferred a reduction in gastric cancer risk. The reduction appeared stronger after 5 years (OR, 0.6; 95% CI, 0.3-1.2) than during shorter follow-up after hip replacement (OR, 0.8; 95% CI, 0.4-1.7). There was an apparent decrease in risk with increasing body weight-adjusted doses of antibiotics (P = 0.13). However, the rate of H. pylori antibody disappearance was not strikingly higher in the cohort of patients undergoing hip replacement than in a control cohort. Our findings provide indirect support for the hypothesis that treatment with antibiotics at a relatively advanced age reduces the risk of gastric cancer.

Carcinoma of the Gastric Cardia: Surgical Practices and Short-term Operative Results in a Defined Swedish Population

Abstract: Adenocarcinoma of the gastric cardia has one of the most rapidly increasing incidence rates of all tumors in Western countries. The aim of this population-based investigation was to study surgical practices and postoperative morbidity and mortality during routine hospital care. The study comprised 176 patients given a new diagnosis of adenocarcinoma of the gastric cardia from February 1, 1989 to the January 31, 1995 in five Swedish counties. The tumor was resectable in 100 (57%) patients (in 36% of the women and 64% of the men), but only 46% of all patients could be offered a potentially curative operation. A total gastrectomy was performed in 54 patients and a proximal gastric resection in 44. Postoperative complications occurred in 39%: in 20% of the patients under age 60 years and in 47% of those aged 60 and over (p= 0.006). Seventeen operated patients (13%) died before discharge. The hospital mortality increased from 3% among those 69 years (p= 0.041). Surgical treatment of carcinoma of the gastric cardia carries substantial morbidity and mortality. No important progress seems to have taken place since the 1960s.