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A Wolk

Publications and source records attributed to A Wolk.

At least 91 records · Page 5Linked to original sources
PubMed1997

Reliability of retrospective information on diet 20 years ago and consistency of independent measurements of remote adolescent diet.

Although dietary exposures in the distant past are considered important in the etiology of several diseases, few studies have addressed methodological aspects of long-term (> or = 20 yrs) recall. We evaluated the reliability of retrospective self-reports about diet 20 years before the interview and consistency (between siblings) of self-reports about diet during adolescence in a population-based case-control study of stomach cancer in Sweden. Short-term reliability (a questionnaire self-administered 9-12 mos after the personal interview) of reports on diet 20 years ago by 374 control subjects showed mean correlation coefficients for 42 foods/beverages of 0.41 (Pearson) and 0.46 (Spearman) and a mean weighted kappa statistic of 0.42; for 15 nutrients/food constituents the corresponding mean values were 0.46, 0.47, and 0.42, respectively. Consistency of independent reports by siblings about their own diet during adolescence studied in 201 control-sibling pairs was modest. The mean Pearson correlation coefficient for 33 foods/beverages was 0.29, and the mean weighted kappa statistic was 0.30; at the nutrient level the means were 0.26 and 0.24, respectively. A comparison of intersibling differences between controls and stomach cancer cases revealed correlations of a similar magnitude (mean Pearson correlation for 33 foods = 0.29 for control-sibling and 0.27 for case-sibling pairs), thus contradicting differential recall. Our results imply that although reliability of self-reports about the diet in the distant past is generally lower than for the actual diet, we can use these measurements when remote time periods are of special interest in etiological epidemiologic studies.

Adolescent↗
PubMed1997

Lipid profile and socioeconomic status in healthy middle aged women in Sweden.

STUDY OBJECTIVE: To examine the relationship between socioeconomic status (SES) and full lipid profile in middle aged healthy women. PARTICIPANTS: These comprised 300 healthy Swedish women between 30 and 65 years who constitute the control group of the Stockholm female coronary risk study, a population based, case-control study of women with coronary heart disease (CHD). The age matched control group, drawn from the census register of greater Stockholm, was representative of healthy Swedish women aged 30-65 years. Five measures of SES were used; educational level, occupation, decision latitude at work, annual income, and size of house or apartment. MAIN RESULTS: Swedish women with low decision latitude at work, low income, low educational level, blue collar jobs, and who were living in small houses or apartments had an unhealthy lipid profile, suggesting an increased risk of CHD. Part of this social gradient in lipids was explained by an unhealthy lifestyle, but the lipid gradients associated with decision latitude at work and annual income were independent of these factors. Decision latitude, educational level, and annual income had the strongest associations with lipid profile. These associations were independent of age, menopausal status, smoking, sedentary lifestyle, alcohol consumption, obesity, excess abdominal fat, and unhealthy dietary habits. Of the lipid variables, low high density lipoprotein cholesterol (HDL) levels were most consistently associated with low SES. CONCLUSIONS: Decision latitude at work was the strongest SES predictor of HDL levels in healthy middle aged Swedish women, after simultaneous adjustment for other SES measures, age, and all lifestyle factors in the multivariable regression model.

Adult↗
PubMed1997

Diet and risk of renal cell cancer: a population-based case-control study.

In a few previous studies on diet and renal cell cancer, an inconsistent positive association with meat, milk, and protein and a negative association with vegetable and fruit consumption have been found. Whereas earlier studies have dealt with recent diet only, our study explored the effect of foods consumed both during the usual adult lifetime and 20 years prior to interview. The study included 379 individuals with incident histologically verified renal cell cancer and 350 control subjects residing in eight counties in Sweden between June 1989 and December 1991. Usual adult dietary intake and dietary habits 20 years prior to interview were assessed by a structured face-to-face interview and a self-administered questionnaire, respectively. Odds ratios were estimated through unconditional logistic regression. We have not observed an association of renal cell cancer with milk or total meat consumption per se; however, frequent intake of fried/sautéed meat increased the risk of renal cell cancer by about 60%; frequent consumption of poultry was also associated with an increased risk (P for trend, 0.05). A significantly protective effect on risk of renal cell cancer was observed with increasing consumption of fruit (P for trend, 0.05). When analyzed by smoking status, total fruit and especially citrus fruit consumption among nonsmokers showed an even stronger protective effect; the highest quartiles of total fruit, apple, and citrus fruit consumption entailed a 50-60% reduction in risk of renal cell cancer compared with the lowest quartiles. There was a suggestion of a protective effect of high total vegetable consumption. A protective effect of vitamin C and alpha-tocopherol was also more pronounced in nonsmokers (P for trend, 0.004 and 0.007, respectively). Our study adds to the evidence that diet may have an important role in the etiology of renal cell cancer.

Aged↗
PubMed1996

Energy, nutrient intake and prostate cancer risk: a population-based case-control study in Sweden.

The role of diet in the etiology of prostate cancer remains unclear, because results from several case-control and cohort studies on fat intake and risk of prostate cancer have been inconsistent; few of the studies have adjusted the results for caloric intake. To examine the relationship between energy, intake of several nutrients and risk of prostate cancer (all stages combined and advanced stages separately), we conducted a population-based case-control study in Orebro County, Sweden, from 1989 through 1994. A total of 526 patients with newly diagnosed prostate cancer and 536 controls, randomly selected from the population register and frequency-matched by age, were included in the analyses. Information about dietary intake was obtained from a self-administered semi-quantitative food frequency questionnaire. Odds ratios with 95% confidence intervals were estimated by unconditional logistic regression. In age-adjusted analyses, there were positive associations of prostate cancer (all stages combined) risk with total energy intake as well as intake of total fat (saturated and monounsaturated), protein, retinol and zinc. The positive association with energy intake was stronger for advanced cancer, with an excess risk of 70% for the highest quartile vs. the lowest. After adjustment for energy intake, there was no apparent association of prostate cancers (all stages combined) with any of the investigated nutrients. However, a weak positive association between intake of retinol and advanced cancer was observed. We conclude that our results provide some evidence that total energy intake is a risk factor for prostate cancer.

Adult↗
PubMed1996

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

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

Adult↗
PubMed1996

A prospective study of smoking and risk of prostate cancer.

We evaluated the hypothesis that smoking increases the incidence of and mortality from prostate cancer. High-quality smoking information was collected in 1971-1975 in a nation-wide cohort of 135,006 male construction workers in Sweden. We achieved virtually complete follow-up through record linkages and ascertained as of December 1991 2,368 incident cases of prostate cancer and 709 deaths due to this disease. Rate ratios (RR) of prostate cancer incidence and mortality, with 95% confidence intervals (CI), were estimated in Poisson-based age-adjusted models, with amount and duration of smoking as independent variables. We found no convincing association between current smoking status, number of cigarettes smoked or years since onset and risk of prostatic cancer. The age-adjusted incidence RR among previous smokers was 1.09 and among current smokers 1.11 compared with non-smokers. Weak and inconsistent trends were seen with increasing number of cigarettes smoked per day and increasing duration among current smokers. Smokers of 15 or more cigarettes daily for at least 30 years experienced an incidence RR of 1.30. Mortality in ex-smokers was similar to that in never-smokers; it was, however, slightly increased among current smokers without any trend with amount smoked or duration. The weak and inconsistent associations between smoking and prostate cancer could easily have arisen due to bias or confounding. We therefore conclude that smoking is most likely not causally linked to the occurrence of prostate cancer.

Adult↗
PubMed1996

Perinatal characteristics in relation to incidence of and mortality from prostate cancer.

OBJECTIVE: To test the hypothesis that factors causing morbidity and mortality from prostate cancer may operate in utero. DESIGN: Matched case-control study of singleton men born between 1874 and 1946 at one hospital. SETTING: Uppsala University Hospital. SUBJECTS: 250 patients with prostate cancer and 691 controls, including 80 patients who died from prostate cancer and their 196 matched controls. MAIN OUTCOME MEASURES: Mother's age at menarche, parity, pre-eclampsia or eclampsia before delivery, age at delivery and socioeconomic status; case or control's birth length and weight, placental weight, prematurity derived from gestational age, and presence of jaundice. RESULTS: Both pre-eclampsia (odds ratio 0, 95% confidence interval 0 to 0.71) and prematurity (0.31, 0.09 to 1.04) were inversely associated with incidence of prostate cancer. Among subjects born full term, placental weight, birth weight, and ponderal index (weight/height 3) showed non-significant positive associations with prostate cancer incidence, and stronger associations with mortality. CONCLUSION: Prenatal exposures that are likely correlates of pregnancy hormones and other growth factors are important in prostate carcinogenesis and influence the natural course as well as the occurrence of this cancer.

Age Factors↗
PubMed1996

International renal cell cancer study. VII. Role of diet.

We investigated the role of diet in the etiology of renal cell cancer (RCC) in a multi-center, population-based case-control study conducted in Australia, Denmark, Sweden and the United States, using a shared protocol. A total of 1,185 incident histopathologically confirmed cases (698 men, 487 women) and 1,526 controls (915 men, 611 women) frequency-matched to cases by sex and age were included in the analyses. The association between RCC and diet was estimated by relative risks (RR) and 95% confidence intervals (CI) adjusted for age, sex, study center, body mass index and smoking. A statistically significant positive association was observed for total energy intake (RR = 1.7, 95% CI = 1.4-2.2 for the highest vs. lowest quartile, p value for trend < 0.00001), while the hypothesis that protein and fat are risk factors independent of energy was not supported. Fried meats were associated with increased RCC risk, while vegetables and fruits were protective, with the strongest effect observed for the highest quartile of consumption of orange/dark green vegetables but not vitamin C or beta carotene. Increased risk was associated with low intake (lowest decile) of vitamin E and magnesium. We observed an apparent protective effect of alcohol confined to women and probably due to chance. Our findings indicate an important role of nutrition in the development of RCC. The apparent positive association of energy intake with risk of RCC needs further investigation in a prospective cohort study to exclude the possible impact of differences in recall between cases and controls.

Adult↗
PubMed1996

Nutrition and renal cell cancer.

Epidemiologic evidence on the relation between nutrition and renal cell cancer is reviewed. Kidney cancer, comprising 1.7 percent of all malignant diseases diagnosed worldwide, shows about a 20-fold international variation in the incidence in men and 10-fold in women. This substantial variation indicates an important causal role of environmental factors. Renal cell (parenchymal) cancer (RCC) accounts for about 80 percent of all kidney cancers. While the etiology of RCC is incompletely understood, analytic epidemiologic studies provide consistent support for a positive association of obesity with risk of RCC; the dose-response observed supports a causal relationship. Only a few prospective studies, all of them limited in size, have been published, while ecologic and case-control studies suggest that diet may be important in the etiology of RCC. However, contradictory results and methodologic limitations in some case-control studies prevent definite conclusions concerning diet and RCC. A positive association of protein and fat intake, as well as their main food sources (meat, milk, fats), with risk of RCC-as suggested by ecologic studies-has no clear support in analytic epidemiologic studies. A protective effect of vegetables and fruits has been observed in most case-control studies, while the majority do not show an association between alcohol, coffee, and risk of RCC. Recent reports indicated an increased risk of RCC associated with consumption of fried/sautéed meat and low intakes of magnesium or vitamin E. An apparent positive association with total energy intake, perhaps due to bias, needs further investigation.

Carcinoma, Renal Cell↗
PubMed1996

Screening for osteopenia and osteoporosis: selection by body composition.

There is a great need for simple means of identifying persons at low risk of developing osteoporosis, in order to exclude them from screening with bone mineral measurements, since this procedure is too expensive and time-consuming for general use in the unselected population. We have determined the relationships between body measure (weight, height, body mass index, lean tissue mass, fat mass, waist-to-hip ratio) and bone mineral density (BMD) in 175 women of ages 28-74 years in a cross-sectional study in a county in central Sweden. Dual-energy X-ray absorptiometry was performed at three sites: total body, L2-4 region of lumbar spine, and neck region of the proximal femur. Using multiple linear regression models, the relationship between the dependent variable, BMD, and each of the body measures was determined, with adjustment for confounding factors. Weight alone, in a multivariate model, explained 28%, 21% and 15% of the variance in BMD of total body, at the lumbar spine and at the femoral neck according to these models. The WHO definition of osteopenia was used to dichotomize BMD, which made it possible, in multivariate logistic regression models, to estimate the risk of osteopenia with different body measures categorized into tertiles. Weight of over 71 kg was associated with a very low risk of being osteopenic compared with women weighing less than 64 kg, with odds ratios (OR) of 0.01 (95% confidence interval (CI) 0.00-0.09), 0.06 (CI 0.02-0.22) and 0.13 (CI 0.04-0.42) for osteopenia of total body, lumbar spine and femoral neck, respectively. Furthermore a sensitivity/specificity analysis revealed that, in this population, a woman weighing over 70 kg is not likely to have osteoporosis. Test specifics of a weight under 70 kg for osteoporosis (BMD less than 2.5 SD compared with normal young women) of femoral neck among the postmenopausal women showed a sensitivity of 0.94, a specificity of 0.36, positive predictive value (PPV) of 0.21, and negative predictive value (NPV) of 0.97. Thus, exclusion of the 33% of women with the highest weight meant only that 3% of osteoporotic cases were missed. The corresponding figures for lumbar spine were sensitivity 0.89, specificity 0.38, PPV 0.33, and NPV 0.91. All women who were defined as being osteoporotic of total body weighed under 62 kg. When the intention was to identify those with osteopenia of total body among the postmenopausal women we attained a sensitivity of 0.92 and a NPV of 0.91 for a weight under 70 kg, whereas we found that weight could not be used as an exclusion criterion for osteopenia of femoral neck and lumbar spine. Our data thus indicate that weight could be used to exclude women from a screening program for postmenopausal osteoporosis.

Absorptiometry, Photon↗
PubMed1996

A search for recall bias in a case-control study of diet and breast cancer.

BACKGROUND: In retrospective studies of dietary habits and breast cancer risk, recall bias is a concern since diet has been publicized as a cause of breast cancer. METHODS: In a case-control study of diet and breast cancer risk nested within a cohort of women screened with mammography, we contrasted answers to a retrospective dietary interview with answers to a dietary questionnaire which was filled out before any diagnostic procedures for breast cancer were undertaken. The source population was all women aged 40-74 in two counties in Sweden invited to mammographic screening and asked to fill out a questionnaire before the screening. Cases and controls were subsequently defined -- matched on age, county of residence, and time of mammography -- and approached for an interview. RESULTS: In all, 265 cases and 431 controls participated in the study. Means of frequencies differed between the agreement in the questionnaire's and the interview's classifications of study subjects into quartiles of monthly intake varied between 31 percent and 57 percent. Kappa statistics in all food groups were below 0.41. In a regression analysis, case subjects with low responses on the questionnaire about intake of meat, snacks, and coffee and tea gave higher responses on interview than did controls who had low questionnaire responses for these food groups. The reverse was also true: cases' responses that were high on the questionnaire were lower on interview for these food groups than were controls' responses. CONCLUSIONS: We found few signs of recall bias, and the few indications of a differential misclassification that we found were not in food groups that have been publicly discussed as causes of breast cancer.

Adult↗
PubMed1996

Effect of prefracture versus postfracture dietary assessment on hip fracture risk estimates.

BACKGROUND: Dietary factors are presumed to have influence on bone mass and hence fracture susceptibility. Most information in this respect is based on retrospective assessment of previous dietary habits. In a population-based case-control study nested within a cohort, we collected dietary information both before and after a first hip fracture. Thus it was possible to study reported changes in dietary habits, intentional as well as unintentional, among hip fracture patients after a first hip fracture and to compare postfracture with prefracture dietary information. METHODS: More than 65 000 women born 1914-1948 in two counties in central Sweden completed a food frequency questionnaire regarding their usual current dietary habits, before attending a mammographic screening between the years 1987 and 1990. Subsequently 123 of them sustained a first hip fracture and were defined as cases in the present study. For every case, one control, individually matched by age and county of residence, was selected from the cohort. A second identical food frequency questionnaire was mailed to both cases and controls on average 2 years after the hip fracture event. In total 98 case/control pairs could be included in the analysis. The association between diet and hip fracture was evaluated and the results from the two dietary assessments were contrasted. Women who themselves claimed that they had not changed their diet in recent years were analysed separately. RESULTS: The hip fracture cases, compared with the controls, had reduced their reported dietary intake of dairy products after the fracture. Apparently this was not intentional since this effect was more pronounced among those cases who claimed that their diet was unchanged. The changes were most apparent among the younger cases with a more recent hip fracture and with a body mass index above the median. Half of the cases, more than twice the frequency in controls, who were initially classified as having high intake of dairy products were classified as having low intake (<800 mg calcium/day) after the hip fracture. This also lowered, in fact reversed, the relative risk estimates of hip fracture both for intake of dairy products and calcium. Crude odds ratios of highest quartile of intake versus lowest, changed from 3.0 to 0.6 for dairy products and from 2.6 to 0.9 for calcium. No other foods or nutrients displayed such notable differences between the two surveys. CONCLUSION: We conclude that the use of current and retrospective dietary information after a hip fracture can lead to a differential misclassification in dietary studies and to biased estimates of hip fracture risk as compared with prospectively collected dietary information.

Age Distribution↗
PubMed1996

Obesity and self-perceived health in Sweden.

Data on self-perceived health in relation to relative body weight from the nationally representative adult Swedish population (12988 men and 13414 women) obtained from Statistics Sweden were analysed. The results are adjusted for age, socio-economic groups, self-reported chronic disease and marital status. Obesity was associated with 40% higher prevalence of severe pains from several joints in men and women and higher consumption of analgetics (OR = 1.6, 95% CI 1.2-2.2, in men, OR = 1.9, 95% CI 1.6-2.3, in women). Overweight and more often obese subjects reported physical impairment and in particular reduced mobility (OR = 1.9, 95% CI 1.5-2.5 in obese men and OR = 2.4, 95% CI 2.0-2.9 in obese women). Intake of vitamins was 20-40% significantly lower in overweight and obese than in normal weight subjects; the intake of iron pills was 60% lower in obese women. Dental status was worse in overweight and obese subjects. Dentures were found more often in overweight (OR = 1.5, 95% CI 1.3-1.7) and obese women (OR 2.2, 95% CI 1.9-2.7) in comparison to those with normal weight. Underweight was associated with adverse self-perceived health with regard to all these indicators. Our findings suggest that already moderate overweight in particular in women results in reduced mobility and physical impairment.

Adolescent↗
PubMed1996

Lifestyle factors and prostate cancer risk: a case-control study in Sweden.

We examined associations between lifestyle factors and subsequent risk of prostate cancer in a population-based case-control study. Information on smoking and alcohol habits, socioeconomic factors, marital status, family history, and sexual habits were obtained from a questionnaire and a face-to-face interview with 256 (74.6%) eligible patients and 252 (76.6%) selected controls, frequency matched by age and screened for prostate cancer with negative findings. Unconditional logistic regression was used to estimate the odds ratios (ORs). Risk was elevated among current smokers of cigarettes (OR, 1.8) and current users of hard liquor (OR, 1.4); however, the lack of dose-response trend for both of these exposures argues against a causal association. We found tentative evidence that early first intercourse, a larger number of sexual partners, and other indices of high sexual activity are associated with increased risk. Similarly, adult height, an indicator of nutrition during childhood and adolescence, was weakly positively associated with risk, although larger studies are needed to establish this link. Unmarried men had a lower risk than married men (OR, 0.3), and socioeconomic status did not appear to be strongly associated with prostate cancer. Men with a father who had prostate cancer had a more than 2-fold increased risk of prostate cancer, whereas those with a brother affected had about a 5-folk risk.

Adult↗