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Biomedical subjects

A Wolk

Publications and source records attributed to A Wolk.

At least 109 records · Page 6Linked to original sources
PubMed1995

Diet, bone mass, and osteocalcin: a cross-sectional study.

To determine the relationships among nutrients intake, bone mass, and bone turnover in women we have investigated these issues in a population-based, cross-sectional, observational study in one county in central Sweden. A total of 175 women aged 28-74 at entry to the study were included. Dietary assessment was made by both a semiquantitative food frequency questionnaire and by four 1-week dietary records. Dual energy X-ray absorptiometry was performed at five sites: total body, L2-L4 region of the lumbar spine, and three regions of the proximal femur. Serum concentrations of osteocalcin (an osteoblast-specific protein reflecting bone turnover) were measured by a radioimmunoassay. Linear regression models, with adjustment for possible confounding factors were used for statistical analyses. A weak positive association was found between dietary calcium intake as calculated from the semiquantitative food frequency questionnaire and total body bone mineral density (BMD) among premenopausal women. No association emerged between dietary calcium intake and site-specific bone mass, i.e., lumbar spine and femoral neck, nor was an association found between dietary calcium intake and serum osteocalcin. BMD at some of the measured sites was positively associated with protein and carbohydrates and negatively associated with dietary fat. In no previous studies of diet and bone mass have dietary habits been ascertained so carefully and the results adjusted for possible confounding factors. Neither of the two methods of dietary assessment used in this study revealed any effect of calcium intake on BMD at fracture-relevant sites among these healthy, mostly middle-aged women.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1995

The aetiology and pathogenesis of human breast cancer.

Whilst investigators have clearly shown that non-hereditary factors dominate the aetiology of human breast cancer, they have failed to identify quantitatively important causes, and prospects for prevention remain indeed limited. However, progress in epidemiological and basic research has taken place during the last few years. Current evidence suggests that breast cancer may be affected by the intra-uterine environment, that exposures during adolescence are particularly important, and that pregnancy has a dual effect on breast cancer risk: an early increase followed by long-term protection. Great variation exists in the structural development of the breast ductal system already in the newborn--and by inference in utero--and a pregnancy induces permanent structural changes in the mammary gland. We suggest that these observations fit into an aetiological model with the following key components: (1) breast cancer risk depends on the number of cells at risk, the susceptibility of individual cells to malignant transformation, and on the degree of cellular proliferation, notably cells which can act as founders of breast cancer; (2) the number of target cells is determined by the hormonal environment mainly early in life, perhaps already in utero; (3) in adult life, hormones which are non-genotoxic, increase breast cancer risk by increasing selective cell proliferation and thus number of target cells and the risk of retention of spontaneous somatic mutations; (4) while a pregnancy stimulates the growth of already malignant cells or cells close to malignant transformation (and thereby entails a short-term risk increase) the dominating long-term protection occurs due to permanent structural changes, terminal differentiation and perhaps decreased cell proliferation and carcinogen-binding in combination.

Adult↗
PubMed1995

Diet and hip fracture risk: a case-control study. Study Group of the Multiple Risk Survey on Swedish Women for Eating Assessment.

BACKGROUND: The role of diet as a risk factor for osteoporotic fractures is unclear. Earlier studies have yielded conflicting results. METHODS: In two counties in central Sweden we investigated the association between dietary intake and the risk of proximal femoral fractures in a case-control study nested in a cohort. Women born in 1914-1948 were asked to fill out a food frequency questionnaire when invited to attend for mammographic screening between the years 1987 and 1990. More than 65,000 women completed the questionnaire. Those who had participated in the enquiry and subsequently sustained a first hip fracture were defined as cases. For every case, four individually matched controls, by age and county of residence, were selected from the cohort. A second questionnaire concerning confounding factors was mailed to controls and cases. In all, 247 cases and 893 controls could finally be included. Monthly intake of foods and daily intake of nutrients were calculated. RESULTS: When highest quartile of intake was compared to lowest, intakes of iron (adjusted odds ratio [OR] of 3.3, 95% confidence interval [CI]: 1.6-6.9), magnesium (adjusted OR = 2.7, 95% CI: 1.3-6.0) and vitamin C (adjusted OR = 1.9, 95% CI: 1.2-3.1) were found to be independent risk factors for hip fracture. High calcium intake did not protect against hip fracture. Smoking, low physical activity in leisure time, low body mass index, earlier fracture of the distal forearm and diabetes were all risk factors while postmenopausal hormone replacement therapy protected against hip fracture. DISCUSSION: This large study indicates new dietary risk factors for hip fracture. The association between high dietary intake of iron, magnesium and vitamin C and risk of hip fracture has not been reported previously. Further clinical and experimental studies are needed to confirm these findings and to investigate their mechanism of action.

Adult↗
PubMed1995

Effects of smoking and physical activity on body weight: developments in Sweden between 1980 and 1989.

OBJECTIVES: To study the effects of changes in smoking and exercise habits on body weighty in Sweden. DESIGN: Analysis of factors affecting relative body weight by construction of regression equations using two models: one adjusted for age, education, socioeconomic group, geographical region and nationality, the other further adjusted for cigarette smoking and leisure-time physical activity. SETTING: Cross-sectional interview data derived from the Undersökning om LevnadsFŏrhållanden' (Living Conditions) survey 1980-81 and 1989-89. SUBJECTS: Nationally representative samples of Swedish men and women aged 16-84. MAIN OUTCOME MEASURES: Changes in body-mass index (BMI) in Sweden during the 1980s. RESULTS: Using the first model, an increase in the BMI of 0.23 kg/m2 in men and 0.17 kg/m2 in women, from 1980 to 1989, was found. When controlling for smoking and physical activity, these values were 0.20 and 0.18 kg/m2, respectively. (P at least < 0.003). CONCLUSIONS: These findings indicate that the reported decrease in smoking and changes in physical activity during the 1980s only marginally explain the BMI increase in the adult Swedish population. The health programmes launched during the 1980s seem to have little beneficial effects on body-weight development, in particular in younger generations of both sexes.

Adolescent↗
PubMed1995

Alcohol intake and breast cancer risk: effect of exposure from 15 years of age.

Research regarding the relationship between alcohol intake and breast cancer risk has suggested an association between the two, although the data are inconsistent regarding dose effects and susceptible populations. To clarify these issues, we investigated the association of breast cancer risk with alcohol intake at various ages in a population-based case-control study nested within a screening cohort in Sweden. Subjects were women 40-75 years old who participated in a screening program in central Sweden. Information about personal characteristics, diet, and alcohol intake was obtained by a questionnaire sent out at the invitation to the screening interview and at a supplementary interview conducted among a sample of women who did and did not develop breast cancer. Alcohol intake did not affect breast cancer risk among women under 50 years old. However, among those over 50 years of age, ever-drinking conferred a relative risk of 1.8 (95% confidence interval = 1.2-2.6). Current and former drinkers had similar increases in risk. No particular latent period of alcohol effect was identified, but drinking later in life to have a bigger effect than did drinking earlier in life.

Adolescent↗
PubMed1994

Diet and breast cancer risk. Results from a population-based, case-control study in Sweden.

BACKGROUND: We describe an epidemiologic analytical study of the relationship between current diet and breast cancer risk. METHOD: The study design is a case-control analysis. Cases were recruited from a mammography screening program used within the national health care system; the control subjects were selected from subjects free of breast cancer in the same population. A total of 380 cases and 525 control subjects, frequency-matched for age, month of mammography, and county of residence, were identified. Of these, 265 cases and 432 control subjects were included in this analysis. Odds ratios for breast cancer in relation to food and nutrient intake were the main outcome measures. RESULTS: Exposure in the highest quartile of beta-carotene intake gave an odds ratio of 0.6 (95% confidence interval, 0.4 to 1.0). No increased risk was noted with high fat intake. Breast cancer risk was associated with alcohol intake only when alcohol was analyzed in quartiles: odds ratio, 1.6 (95% confidence interval, 1.0 to 2.4) for the highest quartile of intake vs the lowest. Stratified analyses showed that a high fat intake might decrease the protective effect of beta-carotene intake. Risks did not change appreciably with adjustment for total energy intake or known breast cancer risk factors. CONCLUSIONS: As in most other studies, no strong risk factors for breast cancer have been identified in the current diet. The negative association between breast cancer risk and beta-carotene intake may be supported by a plausible mechanism, but our finding concerning alcohol should be interpreted cautiously since there was no dose-response relationship and the biological mechanism for a threshold effect at very low levels of consumption is unclear.

Adult↗
PubMed1994

Nutrients and gastric cancer risk. A population-based case-control study in Sweden.

A population-based case-control study of gastric cancer was conducted in areas with contrasting incidence rates in Sweden. Face-to-face interviews were carried out with 338 (74.1%) of all eligible cases and 679 (77.3%) of the selected controls. Consumption of selected nutrients during adolescence and 20 years prior to interview was estimated, together with life-time intake of vitamin supplements. Ascorbic acid and beta-carotene had an unequivocal protective effect, but alpha-tocopherol and nitrate were also negatively associated with gastric-cancer risk. In a multivariate analysis including all of these factors, only ascorbic acid remained a significant protective factor. The only macronutrient positively associated with the risk of gastric cancer was fat: intake 20 years prior to interview, but not during adolescence, was found to have a significant impact. Supplementation with vitamins almost halved the risk after adjustment for dietary intake of the corresponding vitamins. While the protective effect of vitamin C and beta-carotene could conceivably be ascribed to other agents in the diet, the strong negative association between supplementation with vitamin C and risk of gastric cancer supports the hypothesis of a protective role of this anti-oxidant.

Age Factors↗
PubMed1994

Tobacco, alcohol and the risk of gastric cancer. A population-based case-control study in Sweden.

Previous studies have provided conflicting information on the role of tobacco and alcohol in gastric carcinogenesis. A population-based case-control study with 338 histologically confirmed gastric-cancer cases and 679 control subjects was conducted. Information relating to life-time tobacco consumption, alcohol intake and diet during adolescence and 20 years before interview, and to socio-economic conditions was obtained through face-to-face interviews. Current cigarette smokers were found to have a greater risk than non-users of tobacco. The duration of cigarette or pipe smoking was positively associated with gastric-cancer risk. There was significant interaction between tobacco use and fruit consumption. High fruit intake was more protective among users of tobacco than among non-users, and the risk estimates associated with cigarette smoking were higher among those with low fruit consumption than among frequent fruit-eaters. Likewise, though to a lesser extent, vegetable intake interacted with tobacco use. Snuff dipping and alcohol intake was not associated with gastric-cancer risk. However, high alcohol intake tended to increase the risk associated with tobacco use. This study adds further support to the role of tobacco smoking in gastric carcinogenesis, and demonstrates that high intake of fruits and vegetables may be particularly beneficial in smokers.

Adult↗
PubMed1994

Early-life risk indicators of gastric cancer. A population-based case-control study in Sweden.

Exposures early in life seem to play an important role in the development of gastric cancer, but their nature is not well understood. In a population-based case-control study, we examined weight, height and body-mass index (BMI) at the age of 20 as well as indices of socioeconomic conditions. Face-to-face interviews were conducted with 338 of 456 eligible histologically confirmed gastric cancer patients and 679 of 880 eligible control subjects, sampled from population registers and frequency matched by age and gender. Gastric cancer risk was negatively associated with height. Risk was positively, associated with weight at age 20 in both sexes. The highest BMI-quartile was associated with an increased risk. This association between BMI and risk was confined to BMI at age 20, and disappeared for BMI 20 years prior to interview. High socioeconomic status (SES) as well as long education carried a decreased risk of gastric cancer. Number of siblings was positively associated with risk. Factors related to short stature and high adolescent body weight are associated with an increased risk of gastric cancer, as is a high number of siblings. These factors may reflect influences of dietary patterns early in life.

Adolescent↗
PubMed1994

Risk factors for oesophageal cancer in northeast China.

A hospital-based case-control study of oesophageal cancer was carried out in the Heilongjiang Province, a low-risk area for oesophageal cancer in China. From May 1985 to May 1989, 196 histologically confirmed cases and 392 controls with other (non-neoplastic) diseases were personally interviewed in the wards of 5 major hospitals. Information was obtained about usual consumption in the early 1980s of 32 major contributors to the diet in the province, socio-demographic status, smoking and alcohol consumption. Odds ratios (OR) were obtained from logistic regression models, and confounding was controlled by means of multivariate models. Smoking and alcohol consumption were major risk factors for oesophageal cancer in this population. Smokers of handmade cigarettes exhibited a particularly high risk. A near multiplicative synergism was found between smoking and alcohol consumption. There was a significant inverse dose-risk trend for combined consumption of vegetables and fruits; a 300-g increase per day lowered risk by 35%. Vitamin C intake was negatively associated with risk; a 100-mg increase per day lowered risk by 39%. Our data suggest a modifying effect of vitamin C and beta-carotene on risk associated with smoking, but the power of analyses was low. Salt, salt-preserved foods and pickled vegetables were not associated with increased risk. High temperature of meals and drinks was a strong risk indicator in this population. The strength of tea and overall tea consumption were independent determinants of the risk.

Adult↗
PubMed1994

Self-administered food frequency questionnaire: the effect of different designs on food and nutrient intake estimates.

BACKGROUND: Our objective was to determine the possible influence that different designs of a food frequency questionnaire might have on food, energy and nutrient intake estimates. METHODS: A population-based survey included 6783 women, 40-70 years old, living in central Sweden. Using a factorial study design, we compared eight different types of questionnaire covering combinations of three factors: increasing/decreasing frequency categories; addition of portion sizes; and addition of non-dietary questions. All questionnaires included the same list of 60 food items. One of the eight questionnaires was mailed to each subject according to a random assignment. The overall response rate was 77%. RESULTS: Compared with increasing frequencies, decreasing order of frequency categories entailed 3-11% higher estimates of mean intake for 7 of 14 food groups, 4% higher estimates for energy and 3-6% higher estimates for 13 of 18 nutrients. Addition of portion sizes had heterogeneous effects, both on dietary items (e.g. from -30% decrease for eggs to +76% increase for coffee) and on calculated nutrients (from -7% for beta-carotene to +19% for vitamin C). The inclusion of some additional non-dietary questions did not influence the estimated mean intake of any food or nutrient. CONCLUSIONS: The results of this study have implications for the design of questionnaires and for pooled analyses in nutritional epidemiology, when different food questionnaires are used.

Adult↗
PubMed1994

The role of obesity and weight fluctuations in the etiology of renal cell cancer: a population-based case-control study.

The causes of renal cell cancer (RCC) are poorly understood. Besides smoking, obesity remains the only risk factor that is fairly well established. The association between obesity and RCC appears stronger and more consistent in women than in men. We investigated the question of whether this apparent sex difference could be explained by repeated weight changes (weight cycling), less physical exercise, or pharmacological treatment of obesity in women. Structured face-to-face interviews were carried out with 379 (70% of all eligible) incident cases of RCC and 353 (72% of eligible) controls. The relationships between RCC and adult height, weight, and body mass index (BMI), defined as weight/height, were analyzed. Odds ratios (ORs) were estimated through logistic regression. No association was found between adult height and RCC. In men, weight and BMI appeared at most to be weakly related to risk of RCC. In women, higher adult weight and BMI (usual, highest, and lowest) and also high BMI at ages 30, 40, and 50 years were consistently associated with a significantly increased risk of RCC. Women with an usual adult BMI in the top 5% had a nearly 3-fold increased risk of RCC [OR, 2.67; 95% confidence interval (CI), 1.02-7.01]. Compared with individuals with no weight-loss periods, 2 or more such periods implied an OR of 0.96 (95% CI, 0.32-2.90) in men and 3.87 (95% CI, 1.20-12.45) in women. Physical activity at work reduced the risk of RCC in men but not women. Regular use of diet pills containing amphetamine was associated with an increased risk of RCC (OR, 4.06; 95% CI, 1.35-12.22).(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1993

Diet and risk of gastric cancer. A population-based case-control study in Sweden.

A case-control study to evaluate risk factors of gastric cancer was carried out in areas with contrasting incidence rates in Sweden. Face-to-face interviews were conducted with 338 of 456 eligible histologically confirmed gastric-cancer cases and 669 of 880 eligible control subjects, sampled from population registers and frequency-matched by age and gender. We focused on 2 periods, adolescence and 20 years prior to interview. The association of gastric-cancer risk with dietary habits during adolescence were similar to that found for the period 20 years before interview; high consumption of wholemeal bread, fruit and vegetables was associated with reduced gastric-cancer risk. In addition, cheese, fish and tea had a protective effect during adolescence. Increased gastric-cancer risk was related to whole-milk consumption, but this association decreased substantially in a multivariate analysis including vegetables. There was a positive relationship between gastric-cancer risk and the age at which the interviewees started using refrigerators. This population-based study confirmed the protective effect of a high consumption of vegetables and fruit in the development of gastric cancer, but failed to find any association between intake of meat, sausage, cold cuts, liver, salt, coffee, the habit of frying, smoking or grilling foods, and risk of gastric cancer.

Adult↗
PubMed1992

Alcoholism and cancer risk: a population-based cohort study.

The incidence of cancer was studied in a population-based cohort of 9,353 individuals (8,340 men and 1,013 women) with a discharge diagnosis of alcoholism in 1965-83, followed up for 19 years (mean 7.7). After exclusion of cancers in the first year of follow-up, 491 cancers were observed cf 343.2 expected through 1984 (standardized incidence ratio [SIR] = 1.4, 95 percent confidence interval [CI] = 1.3-1.6). A similar excess risk of cancer was seen among men (SIR = 1.4, CI = 1.3-1.6) and among women (SIR = 1.5, CI = 1.1-2.0). We observed the established associations with cancers of the oral cavity and pharynx (SIR = 4.1, CI = 2.9-5.7), esophagus (SIR = 6.8, CI = 4.5-9.9), larynx (SIR = 3.3, CI = 1.7-6.0), and lung (SIR = 2.1, CI = 1.7-2.6), although confounding by smoking likely increased these risk estimates. While there was evidence of increased risk for pancreatic cancer (SIR = 1.5, CI = 0.9-2.3), alcoholism did not elevate the incidence of cancer of the stomach (SIR = 0.9, CI = 6-1.4), large bowel (SIR = 1.1, CI = 0.8-1.5), prostate (SIR = 1.0, CI = 0.8-1.3), urinary bladder (SIR = 1.0, CI = 0.6-1.5), or of malignant melanoma (SIR = 0.9, CI = 0.3-1.9). Among women, the number of breast cancers observed was close to expected (SIR = 1.2, CI = 0.6-2.2), although a significant excess number of cervical cancers occurred (SIR = 4.2, CI = 1.5-9.1).(ABSTRACT TRUNCATED AT 250 WORDS)

Aged↗
PubMed1992

Ultrabithorax is a regulator of beta 3 tubulin expression in the Drosophila visceral mesoderm.

beta 3 tubulin expression accompanies the specification and differentiation of the Drosophila mesoderm. The genetic programs involved in these processes are largely unknown. Our previous studies on the regulation of the beta 3 tubulin gene have shown that upstream sequences guide the expression in the somatic musculature, while regulatory elements in the first intron are necessary for expression in the visceral musculature. To further analyse this mode of regulation, which reflects an early embryonic specification program, we undertook a more detailed analysis of the regulatory capabilities of the intron. The results reveal not only a certain degree of redundancy in the cis-acting elements, which act at different developmental stages in the same mesodermal derivatives, but they also demonstrate in the visceral mesoderm, which forms a continuous epithelium along the body axis of the embryo, an early action of regulators guiding gene expression along the anterior-posterior axis of the embryo: an enhancer element in the intron leads to expression in a subdomain restricted along the anterior-posterior axis. This pattern is altered in mutants in the homeotic gene Ultrabithorax (Ubx), whereas ectopic Ubx expression leads to activity of the enhancer in the entire visceral mesoderm. So this element is likely to be a target of homeotic genes, which would define the beta 3 tubulin gene as a realisator gene under the control of selector genes.

Animals↗
PubMed1991

Further sequence requirements for male germ cell-specific expression under the control of the 14 bp promoter element (beta 2UE1) of the Drosophila beta 2 tubulin gene.

We have investigated a 14 bp promoter element (beta 2UE1) that is required for testis-specific expression of the Drosophila beta 2 tubulin gene. To further elucidate the role of the 14 bp element, we fused different promoter constructs to the E. coli lacZ gene and established transgenic strains with the aid of the Drosophila P-element transformation system. Germ line transformation experiments with constructs in which the element in the beta 2 tubulin gene promoter was exchanged for a related sequence from the promoter region of the Drosophila beta 3 tubulin gene led to a dramatic reduction in the expression of the lacZ gene in the testis. Exchanging the 14 bp promoter element for a similar sequence from the distal promoter of the Drosophila alcohol dehydrogenase gene abolished expression. This might indicate that the sequence differences between the beta 2UE1 and the beta 2UE1-related elements reflect functional differences between these elements. Constructs in which the beta 2UE1 was fused to the hsp70 promoter revealed that testis-specific expression of a marker gene is obtained only when the element is located at the correct distance from the transcription initiation site. However, constructs in which the beta 2UE1 was inserted at about the correct position (between -41 and -54 bp) upstream of a truncated beta 3 tubulin gene promoter did not show any expression. By making beta 2-beta 3 gene promoter fusions it was found that both the region surrounding the beta 3 transcription initiation site as well as the first 116 b of beta 3 leader sequences independently reduce testis-specific expression. These findings suggest that the testis-specific expression of the Drosophila beta 2 tubulin gene underlies a unique regulatory mechanism.

Animals↗