Biomedical subjects

R Bergström

Publications and source records attributed to R Bergström.

At least 37 records · Page 2Linked to original sources

PubMed1999

Evaluating gastric cancer misclassification: a potential explanation for the rise in cardia cancer incidence.

BACKGROUND: Reports of dramatic increases in gastric cardia cancer incidence warrant concern. However, the recent introduction of a separate diagnostic code, the lack of a consensus definition of the cardia area, and the accelerating interest in cardia cancer may affect classification practices. Little is known about the magnitude of cardia cancer misclassification in large cancer registries. METHODS: In a well-defined Swedish population (1.3 million), we uniformly classified all patients with newly diagnosed gastric adenocarcinoma (from 1989 through 1994) with respect to gastric subsite, and we used this patient group as our gold standard. We then evaluated the completeness of the Swedish Cancer Registry in registering gastric adenocarcinomas against this gold standard and, further, assessed the completeness of cardia cancer registration and the rate of falsely included cases to estimate the potential impact on observed incidence trends. RESULTS: Our gold standard contained 1337 case subjects with gastric adenocarcinoma. Overall, the Swedish Cancer Registry was 98% complete with regard to gastric adenocarcinomas and had a 4% rate of falsely included cases. The completeness of coding cardia cancer was only 69%, and the positive predictive value for cardia cancer was 82%, with no improvement over time. CONCLUSIONS: Although overall completeness of gastric cancer registration by the Swedish Cancer Registry was excellent, accuracy in registering cardia tumors was surprisingly low. Our estimates suggest that true cardia cancer incidence could be up to 45% higher or 15% lower than that reported in the Cancer Registry. This margin of error could accommodate the observed increase in cardia cancer in Sweden. Therefore, secular trends in cardia cancer incidence should be interpreted cautiously.

Adenocarcinoma↗

PubMed1999

Fertility patterns after appendicectomy: historical cohort study.

OBJECTIVE: To examine fertility patterns in women who had their appendix removed in childhood. DESIGN: Historical cohort study with computerised data and fertility data for this cohort and for an age matched cohort of women from the Swedish general population. The cohorts were followed to 1994. SETTING: General population. PARTICIPANTS: 9840 women who were under 15 years when they underwent appendicectomy between 1964 and 1983; 47 590 control women. MAIN OUTCOME MEASURES: Diagnoses at discharge. Distributions of age at birth of first child among women with perforated and non-perforated appendix and women who underwent appendicectomy but were found to have a normal appendix compared with control women by using survival analysis methods. Parity distributions at the latest update of the registry were also examined. RESULTS: Women with a history of perforated appendix had a similar rate of first birth as the control women (adjusted hazard ratio 0.95; 95% confidence interval 0.88 to 1. 04) and had a similar distribution of parity at the end of follow up. Women who had had a normal appendix removed had an increased rate of first births (1.48; 1.42 to 1.54) and on average had their first child at an earlier age and reached a higher parity than control women. CONCLUSION: A history of perforated appendix in childhood does not seem to have long term negative consequences on female fertility. This may have important implications for the management of young women with suspected appendicitis as the liberal attitude to surgical explorations with a subsequently high rate of removal of a normal appendix is often justified by a perceived increased risk of infertility after perforation. Women whose appendix was found to be normal at appendicectomy in childhood seem to belong to a subgroup with a higher fertility than the general population.

Adolescent↗

PubMed1999

Symptomatic gastroesophageal reflux as a risk factor for esophageal adenocarcinoma.

BACKGROUND: The causes of adenocarcinomas of the esophagus and gastric cardia are poorly understood. We conducted an epidemiologic investigation of the possible association between gastroesophageal reflux and these tumors. METHODS: We performed a nationwide, population-based, case-control study in Sweden. Case ascertainment was rapid, and all cases were classified uniformly. Information on the subjects' history of gastroesophageal reflux was collected in personal interviews. The odds ratios were calculated by logistic regression, with multivariate adjustment for potentially confounding variables. RESULTS: Of the patients interviewed, the 189 with esophageal adenocarcinoma and the 262 with adenocarcinoma of the cardia constituted 85 percent of the 529 patients in Sweden who were eligible for the study during the period from 1995 through 1997. For comparison, we interviewed 820 control subjects from the general population and 167 patients with esophageal squamous-cell carcinoma. Among persons with recurrent symptoms of reflux, as compared with persons without such symptoms, the odds ratios were 7.7 (95 percent confidence interval, 5.3 to 11.4) for esophageal adenocarcinoma and 2.0 (95 percent confidence interval, 1.4 to 2.9) for adenocarcinoma of the cardia. The more frequent, more severe, and longer-lasting the symptoms of reflux, the greater the risk. Among persons with long-standing and severe symptoms of reflux, the odds ratios were 43.5 (95 percent confidence interval, 18.3 to 103.5) for esophageal adenocarcinoma and 4.4 (95 percent confidence interval, 1.7 to 11.0) for adenocarcinoma of the cardia. The risk of esophageal squamous-cell carcinoma was not associated with reflux (odds ratio, 1.1; 95 percent confidence interval, 0.7 to 1.9). CONCLUSIONS: There is a strong and probably causal relation between gastroesophageal reflux and esophageal adenocarcinoma. The relation between reflux and adenocarcinoma of the gastric cardia is relatively weak.

Adenocarcinoma↗

PubMed1999

Human papillomavirus infection and esophageal cancer: a nationwide seroepidemiologic case-control study in Sweden.

BACKGROUND: Infection with human papillomavirus (HPV) type 16 has been implicated as a risk factor for esophageal squamous cell carcinoma in three seroepidemiologic studies. We conducted a larger, population-based study to verify this association and to investigate possible confounding factors. METHODS: We performed a nationwide case-control study in Sweden of HPV16 or HPV18 infection and risk of esophageal squamous cell carcinoma or esophageal/gastroesophageal adenocarcinoma. Tumors were strictly classified by their location and histologic type. Case subjects with incident cancers and population-based control subjects donated blood samples and were interviewed in person about potential confounding factors. An enzyme-linked immunosorbent assay was used to detect HPV seropositivity. Multivariate analyses were conducted to study relationships between HPV seropositivity, level of education, smoking (all tobacco) status, alcohol consumption, and cancer risk. RESULTS: We compared 121 case subjects with esophageal squamous cell carcinoma and 173 case subjects with adenocarcinoma of the esophagus or gastroesophageal junction with 302 population-based control subjects. The age- and sex-adjusted odds ratios (ORs) for squamous cell carcinoma were 1.0 (95% confidence interval [CI] = 0.5-2.0) for persons seropositive for HPV16 and 0.5 (95% CI = 0.2-1.1) for persons seropositive for HPV18 in comparison with seronegative individuals. The corresponding ORs for adenocarcinoma were 1.2 (95% CI = 0.7-2.2) and 0.2 (95% CI = 0.1-0.7), respectively. Adjustments for smoking status, alcohol consumption, and level of education did not alter the results. CONCLUSIONS: We found no evidence of a positive association between HPV16 or HPV18 infection and either form of esophageal cancer. Our results do not support conclusions from previous studies.

Adenocarcinoma↗

PubMed1999

The role of reproductive factors and use of oral contraceptives in the aetiology of breast cancer in women aged 50 to 74 years.

It is unclear whether age at menarche is causally involved in breast-cancer aetiology, or serves a correlate of other early-life exposures. Other aspects of reproductive life, including cycle length and regularity, climacteric symptoms, reproductive history and oral contraceptive use, are also incompletely investigated. We examined these issues in a population-based case-control study, including 3,016 women aged 50 to 74 years with invasive breast cancer, and 3,263 controls of similar age. Mailed questionnaires and telephone interviews were used to collect information on menstrual and reproductive characteristics as well as use of oral contraceptives. We found a statistically significant negative association between increasing age at menarche and breast-cancer risk in women born before 1925 but not after. Length of the menstrual cycle at age 30 seemed to be adversely related to breast-cancer risk, with OR for women with cycle lengths < 24 days and > 30 days being 0.76 and 1.18, as compared with women with a cycle length of 28 days. There was a strong trend of decreasing breast-cancer risk with increasing parity (OR per borne child 0.85, 95% CI 0.80-0.90). Lactation, menopausal symptoms or past use of oral contraceptives did not appear associated with breast-cancer risk. Our findings provide some evidence of a role of environmental correlates of early menarche in breast-cancer aetiology, and underline the importance of childbirth, especially early in life, in the prevention of breast cancer. Our data are not readily compatible with an important influence of former oral contraceptive use on post-menopausal breast-cancer risk.

Aged↗

PubMed1999

Human fertility does not decline: evidence from Sweden.

OBJECTIVE: To assess changes in human fertility over time. DESIGN: Time-trend analyses and age-period-cohort modeling. SETTING: Sweden, 1983-1993. PATIENT(S): All primiparous women aged > or =20 years during the study period. There were 401,653 women who were identified through the nationwide Medical Birth Register. INTERVENTION(S): None. MAIN OUTCOME MEASURE(S): Risk of subfertility, defined as > or =1 year of involuntary childlessness. RESULT(S): Subfertility problems decreased dramatically over successive maternal birth cohorts. Further, the risk of subfertility increased with age and decreased with increasing formal education. CONCLUSION(S): A decrease in male fertility cannot be ruled out on the basis of these results, but if present, it is minor and totally outweighed by other favorable developments. As the main explanation for our findings, we propose a decrease in the prevalence of secondary subfertility as a result of the eradication of gonorrhea.

Adult↗

PubMed1999

Risks of breast and endometrial cancer after estrogen and estrogen-progestin replacement.

OBJECTIVE: We studied the risk of breast and endometrial cancer in a cohort of 11,231 Swedish women prescribed different replacement hormone regimens. METHODS: All 10,472 women at risk of developing breast cancer and 8,438 women at risk of endometrial cancer were followed up from the time of the questionnaire in 1987-88 through 1993, by record-linkages to the National Swedish Cancer Registry. Using data from a questionnaire we analyzed the relationships between hormone exposures and cancer risk, with non-compliers and users of less than 1 year as a reference group. RESULTS: For breast cancer, women reporting use of estrogens combined with progestins had evidence of an increased risk relative to women denying intake or taking hormones for less than 1 year; relative risk (RR) = 1.4 (95% confidence interval 0.9-2.3) after 1-6 years of intake, and RR = 1.7 (95% CI 1.1-2.6) after more than 6 years. This excess risk seemed confined to recent exposure. We found no association with intake of estrogens alone using non-compliers and short-term takers as the reference group. The risk of invasive endometrial cancer was increased four-fold in women using medium-potency estrogens alone for 6 years or longer, RR = 4.2 (95% CI 2.5-8.4). Women on such long-term progestin-combined treatment had a lower, non-significant, excess risk (RR = 1.4; 95% CI 0.6-3.3). CONCLUSIONS: We conclude that long-term recent use of estrogen-progestin combined replacement therapy may increase the risk of breast cancer. Exposure to estrogen alone substantially elevates the risk of endometrial cancer, an increase that can be reduced or perhaps avoided by adding progestins.

Breast Neoplasms↗

PubMed1999

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

OBJECTIVE: Our purpose was to investigate effects of physical activity on risk for breast cancer. METHODS: From the Swedish nationwide censuses in 1960 and 1970 we defined three partly overlapping cohorts of women whose occupational titles allowed reproducible classification of physical demands at work in 1960 (n = 704,904), in 1970 (n = 982,270), or with the same demands in both 1960 and 1970 (n = 253,336). The incidence of breast cancer during 1971-89 was ascertained through record linkage to the Swedish Cancer Register. We used Poisson regression to estimate relative risks (RR). RESULTS: A total of 20,419, 22,840, and 8261 breast cancers, respectively, were detected in the three cohorts. In all three cohorts the risk for breast cancer increased monotonically with decreasing level of occupational physical activity and with increasing socioeconomic status. Among women with the same estimated physical activity level in 1960 and 1970 the RR was 1.3 for sedentary as compared with high/very high activity level (95% CI 1.2-1.4; p for trend < 0.001). Adjustment for socioeconomic status virtually eliminated this association (RR 1.1; 95% CI 0.9-1.2; p for trend 0.12) leaving a statistically significant 30% gradient only among women aged 50-59 years at follow-up. The association between socioeconomic status and breast cancer risk was largely unchanged after adjustment for occupational physical activity. CONCLUSION: The protective effect of occupational physical activity on breast cancer risk, if any, appears to be confined to certain age groups.

Activities of Daily Living↗

PubMed1999

Retinopathy in diabetic patients aged 15-50 years in the county of Umeå, Sweden.

PURPOSE: To examine the prevalence of diabetic retinopathy and its relation to certain risk factors (glycosylated hemoglobin, blood pressure, serum creatinine, proteinuria, smoking) in a population-based study on a specific age-group of patients with diabetes mellitus in the county of Umeå, Sweden. METHODS: All diabetic patients aged 15-50 years living in the county of Umeå were invited to the study. A standard clinical and eye examination was performed, and seven-field stereoscopic photographs were taken of each eye. Blood and urine samples were collected. Univariate and multivariate statistical analyses were performed. RESULTS: Of the eligible 395 patients 285 (91%) participated in the study. 285 patients (79%) had diabetes mellitus type 1, 71 (20%) subjects had diabetes mellitus type 2, and 3 patients (1%) had secondary diabetes. In the statistical analysis performed on patients with type 1 diabetes mellitus, duration, presence of hypertension, systolic blood pressure, plasma glucose, glycosylated hemoglobin, serum creatinine, proteinuria and smoking all were significantly related to increasing degree of retinopathy when a univariate model was applied. However, when a multivariate analysis was performed only duration, proteinuria, glycosylated hemoglobin and male gender were statistically significantly associated with severeness of retinopathy. CONCLUSION: Increased duration of diabetes, inadequate metabolic control as measured by glycosylated hemoglobin, proteinuria and male gender are factors that are associated with a higher incidence of diabetic retinopathy in diabetes mellitus type 1.

Adolescent↗

PubMed1999

The association of hyperlipidemia with retinopathy in diabetic patients aged 15-50 years in the county of Umeå.

PURPOSE: To study possible associations between serum lipid levels and degree of retinopathy in a population-based study on a specific age-group of patients with diabetes mellitus in the county of Umeå, Sweden. METHODS: All patients with diabetes mellitus aged 15-50 years living in the county of Umeå were invited to the study. The participating subjects had a standard clinical examination and an eye examination performed. Seven-field stereoscopic photographs were taken of each eye, and the photos were sent to Grading Center, Hammersmith Hospital, London, U.K. for grading of the retinopathy. Blood samples were drawn for analysis of lipoprotein(a), high density lipoprotein (HDL) cholesterol, cholesterol and triglycerides. Univariate and multivariate statistical analyses were performed. RESULTS: In the present study only patients with type 1 diabetes mellitus were included, and 285 of the invited 308 diabetic subjects (93%) took part. When univariate analysis was applied we found statistically significant associations between higher lipoprotein(a) levels, higher triglyceride levels, higher cholesterol levels, lower HDL cholesterol/total cholesterol ratios and increasing severeness of retinopathy. However, in the multivariate analysis triglyceride levels lost their importance while all other significant associations were still present. CONCLUSION: Associations were found between higher levels of serum total cholesterol, declining ratios of high density lipoprotein (HDL) cholesterol/total cholesterol, higher levels of serum lipoprotein(a) and more severe retinopathy in diabetes mellitus type 1. No such association was found between serum triglycerides and degree of retinopathy.

Adolescent↗

PubMed1999

Trends in cancer of the cervix uteri in Sweden following cytological screening.

Trends in cervical cancer incidence following the introduction of screening have mostly been studied using cross-sectional data and not analysed separately for squamous cell cancer and adenocarcinomas. Using Swedish nationwide data on incidence and mortality, we analysed trends during more than 3 decades and fitted Poisson-based age-period-cohort models, and also investigated whether screening has reduced the incidence of adenocarcinomas of the cervix. The incidence of reported cancer in situ increased rapidly during 1958-1967. Incidence rates of squamous cell cancer, fairly stable before 1968, decreased thereafter by 4-6% yearly in women aged 40-64, with a much smaller magnitude in younger and older women. An age-cohort model indicated a stable 70-75% reduction in incidence for women born 1940 and later compared with those born around 1923. The incidence of adenocarcinomas doubled during the 35-year study period. The mortality rate increased by 3.6% before 1968 and decreased by 4.0% yearly thereafter. Although a combination of organized and opportunistic screening can reduce the incidence of squamous cell cancer substantially, the incidence of adenocarcinomas appears uninfluenced by screening.

Adenocarcinoma↗

PubMed1999

Efficacy and safety during long-term treatment of primary monosymptomatic nocturnal enuresis with desmopressin. Swedish Enuresis Trial Group.

The Swedish Enuresis Trial (SWEET) was conducted to evaluate the long-term safety and efficacy of intranasal desmopressin treatment in children with primary, monosymptomatic nocturnal enuresis (PMNE). The study had an open, multicentre design and comprised a 4-wk observation period, a 6-wk dose titration period (with 20-40 microg desmopressin) and a 1-y, long-term treatment period. A treatment-free week was introduced every 3 mo to identify dry patients. In total, 399 children aged 6-12 y with PMNE were recruited. Of these, 245 patients (61%) experienced > or = 50% reduction in the number of wet nights during the last 4 wk of dose titration compared with the observation period. These responders entered the long-term phase of the trial. The mean number of wet nights per week decreased from a median of 5.3 (range 1.3-7.0) during the observation period to a median of 0.8 (range 0.0-5.0) during the last 3-mo period. Seventy-seven children became dry, 63 (83%) within 6 mo of treatment initiation. The percentage of children who became dry was similar in all age groups. Significantly fewer children in the lowest age group were defined as responders (52%; 95% CI 45, 59) among the 6-7-y-olds compared to 65% (56, 74) and 81% (72, 90) in the two older age groups. Desmopressin was well tolerated. No serious drug-related adverse events were recorded and no clinical symptoms of hyponatraemia were reported. The SWEET trial has demonstrated that desmopressin is both safe and effective for the long-term treatment of PMNE, with a significant therapeutic effect also in children of 6-7 y of age.

Administration, Intranasal↗

PubMed1999

Survival after rectal cancer: differences between hospital catchment areas. A nationwide study in Sweden.

BACKGROUND: The quality of rectal cancer surgery at small units has been debated. No national studies of this issue have been undertaken and most studies have been based on insufficient data to clarify the controversy. It has been claimed that observed differences in outcomes between specialised centres and smaller hospitals are confounded by differences in stage/severity. AIM: To compare survival after rectal cancer between hospital catchment areas. PATIENTS: All patients with rectal cancer notified to the Swedish Cancer Register in 1973-1992 (n = 30 811) were followed up by record linkage to the nationwide Death Register. METHODS: Relative survival-that is, ratio of observed to expected survival-was computed as a measure of excess mortality attributable to rectal cancer. Multivariate analysis was then performed to estimate the independent effects of hospital catchment area categories and age, year of diagnosis, and duration of follow up. RESULTS: One year relative survival among rectal cancer patients residing in catchment areas of large regional hospitals was 76%, compared with 72% for small local hospitals (p<0.001). A difference was already noted after 30 days and remained five years after diagnosis. Relative survival improved considerably overall, but the differences between catchment area categories persisted. These were not reduced by adjustment for age, time after diagnosis, or time period in multivariate models. CONCLUSION: The differences in outcome between catchment area categories could not be explained by differences in age, time period, or duration of follow up after diagnosis. They are unlikely to be explained by differences between catchment area populations with regard to the average stage of the disease at which symptoms lead to diagnosis. The differences may therefore be attributable to different strategies for diagnosing and managing patients with rectal cancer.

Aged↗

PubMed1998

Excessive dietary intake of vitamin A is associated with reduced bone mineral density and increased risk for hip fracture.

BACKGROUND: The highest incidence of osteoporotic fractures is found in northern Europe, where dietary intake of vitamin A (retinol) is unusually high. In animals, the most common adverse effect of toxic doses of retinol is spontaneous fracture. OBJECTIVE: To investigate whether excessive dietary intake of vitamin A is associated with decreased bone mineral density and increased risk for hip fracture. DESIGN: A cross-sectional study and a nested case-control study. SETTING: Two counties in central Sweden. PARTICIPANTS: For the cross-sectional study, 175 women 28 to 74 years of age were randomly selected. For the nested case-control study, 247 women who had a first hip fracture within 2 to 64 months after enrollment and 873 age-matched controls were selected from a mammography study cohort of 66,651 women 40 to 76 years of age. MEASUREMENTS: Retinol intake was estimated from dietary records and a food-frequency questionnaire. Bone mineral density was measured with dual-energy x-ray absorptiometry. Hip fracture was identified by using hospital discharge records and was confirmed by record review. RESULTS: In multivariate analysis, retinol intake was negatively associated with bone mineral density. For every 1-mg increase in daily intake of retinol, risk for hip fracture increased by 68% (95% CI, 18% to 140%; P for trend, 0.006). For intake greater than 1.5 mg/d compared with intake less than 0.5 mg/d, bone mineral density was reduced by 10% at the femoral neck (P = 0.05), 14% at the lumbar spine (P = 0.001), and 6% for the total body (P = 0.009) and risk for hip fracture was doubled (odds ratio, 2.1 [CI, 1.1 to 4.0]). CONCLUSION: High dietary intake of retinol seems to be associated with osteoporosis.

Adult↗

PubMed1998

Population based case-control study of sick leave in postmenopausal women before diagnosis of hyperparathyroidism.

OBJECTIVE: To analyse sick leave in women at risk of primary hyperparathyroidism before its diagnosis. DESIGN: Case-control study nested within a screened cohort of postmenopausal women. Cases were women with hyperparathyroidism without prior knowledge of their disease and no traditional symptoms or complications. Controls were women from the screened population without hyperparathyroidism. SETTING: Population based screening within a Swedish community. SUBJECT: 48 case-control pairs of women aged 55-70 years. MAIN OUTCOME MEASURE: Sick leave during the 5 years before diagnosis. RESULTS: Total duration of sickness benefits was longer in the cases than controls, and this discrepancy included sick leave on full time or half time and for periods of longer than a week. Cases had an increased risk of sick leave more than half of the investigated time compared with controls (odds ratio 12). Doctors' certificates showed that the overrepresented sick leave in the cases related mainly to cardiovascular diseases. CONCLUSION: Asymptomatic mild primary hyperparathyroidism in postmenopausal women is accompanied by a previously unrecognised morbidity, which has consequences for clinical management of the disorder and its impact on the health economy.

Aged↗

PubMed1998

Insulin-like growth factor 1 and prostate cancer risk: a population-based, case-control study.

BACKGROUND: Recent epidemiologic investigations have suggested an association between increased blood levels of insulin-like growth factor 1 (IGF-1) and increased risk of prostate cancer. Our goal was to determine whether an association exists between serum levels of IGF-1 and one of its binding proteins, insulin-like growth factor-binding protein 3 (IGFBP-3), and prostate cancer risk. METHODS: An immunoradiometric assay was used to quantify IGF-1 levels and IGFBP-3 levels in serum samples as part of a population-based, case-control study in Sweden. The study population comprised 210 patients with newly diagnosed, untreated prostate cancer and 224 frequency-matched control subjects. Data were analyzed by use of unconditional logistic regression to calculate odds ratios (ORs) and 95% confidence intervals (CIs). Reported P values are two-sided. RESULTS: The mean serum IGF-1 level for case patients (158.4 ng/mL) was significantly higher than that for control subjects (147.4 ng/mL) (P = .02); corresponding mean serum IGFBP-3 levels were not significantly different between case patients (2668 ng/mL) and control subjects (2518 ng/mL) (P =.09). We found a moderately strong and statistically significant (P = .04) positive association between serum levels of IGF-1 levels and risk of prostate cancer (OR = 1.51; 95% CI = 1.0-2.26 per 100 ng/mL increment); the association was particularly strong for men younger than 70 years of age (OR = 2.93; 95% CI = 1.43-5.97). No association was found between serum IGF-1 levels and disease stage. Serum IGFBP-3 levels were not significantly associated with increased risk of disease, and adjustment for IGFBP-3 had little effect on the association between IGF-1 levels and risk of prostate cancer. CONCLUSION: Elevated serum IGF-1 levels may be an important predictor of risk for prostate cancer. However, our results do not support an important role for serum IGFBP-3 as a predictor of risk for this disease.

Aged↗

PubMed1998

Risk for endometrial cancer in relation to occupational physical activity: a nationwide cohort study in Sweden.

Notwithstanding its biologic plausibility, the association between physical activity and endometrial cancer has been analyzed in only a few epidemiological studies. Retrospective assessment of exposure and small sample size often hampers interpretation of published data. We studied risk for endometrial cancer in relation to physical activity at work in a large cohort of Swedish women identified in the nationwide censuses in 1960 and 1970, with jobs that could be consistently classified into one of 4 levels of physical demands. Follow-up from 1971 through 1989 was accomplished through record linkages. Multivariate Poisson regression models were used to estimate relative risk. The risk for endometrial cancer increased regularly with decreasing level of occupational physical activity (p for trend < 0.001), and was associated more strongly with activity in 1970 than in 1960. In multivariate analyses, adjusted for age at follow-up, place of residence, calendar year of follow-up, and social class, the relative risk among women with the same physical activity level in 1960 and in 1970 was 30% higher for sedentary as compared with high/very high activity level; (p for trend=0.04). The protective effect of physical activity appeared to be confined to women aged 50 to 69, among whom sedentary work was associated with a 60% higher risk than that observed among women estimated to be physically most active. The excess seemed to disappear within 10 years after a change in physical activity level. Although confounding cannot be ruled out in our data, occupational physical activity appears to reduce the risk for endometrial cancer.

Adult↗

PubMed1998

Body size in different periods of life and breast cancer risk in post-menopausal women.

Adult obesity has been associated with an increased risk of post-menopausal breast cancer, but it is unclear whether this relationship reflects a causal role of obesity during childhood and adolescence, of weight gain during adult life or of adult obesity per se. In a population-based case-control study in all of Sweden, we included 3,345 (84% of all eligible) women aged 50-74 years with invasive breast cancer, and 3,454 (82% of all selected) controls of similar age. Mailed questionnaires and telephone interviews were used to collect detailed information on anthropometric measures. Odds ratios were estimated through multiple logistic regression. Women with the leanest somatotype at age 7 had about a 3-fold higher risk of breast cancer than the most obese (P for trend 0.0009). A suggested protective effect of a high body mass at age 18 and a detrimental influence of body mass 1 year prior to data collection largely reflected the effect of weight gain after age 18, a strong predictor of breast cancer risk. Among women at least 20 years post menopause, those who had gained 30 kg or more since age 18 had an odds ratio of 2.04 (95% confidence interval 1.20-3.48) of breast cancer compared with those who had maintained their weight unchanged. The effect of weight gain was unequivocal among non-users but not among users of hormone replacement therapy. Our findings have important implications, suggesting weight preservation as a means for prevention of post-menopausal breast cancer as well as a causal role of childhood body build in breast cancer etiology.

Age Factors↗