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J A Baron

Publications and source records attributed to J A Baron.

At least 37 records · Page 2Linked to original sources
PubMed2001

Intermediate effect markers for colorectal cancer.

Recurrence or regression of adenomatous polyps is considered to be both a biomarker of risk and an intermediate (surrogate) end-point. The observational epidemiology of adenomas resembles closely that of invasive cancer, and the findings in chemoprevention trials that have been completed closely mirror that common epidemiology. Although it is possible that both the clinical trials and the epidemiology may be wrong, these common findings suggest that adenomas in general are valid end-points. Aberrant crypt foci show promise as biomarkers, both as markers of risk and as intermediate end-points for chemoprevention trials. If issues of cost can be overcome, assessment of ras mutations in stool appears to be a promising technique for screening for large bowel neoplasms. The lack of specificity of the technique limits its utility as a sole end-point in prevention studies, however. Mucosal proliferation has been used both as a biomarker of risk and as an intermediate end-point. The utility of these measures is not clear, however, since there has been discordance between the epidemiological findings regarding proliferation and established risk factors for colorectal neoplasia. The inherent variability of the measures and the technical problems associated with their use are further impediments. However, rectal mucosal proliferation may be suitable for studies in single institutions, or in consortia with very aggressive quality control.

Adenomatous Polyps↗
PubMed2000

Prognosis of cancers associated with venous thromboembolism.

BACKGROUND: Little is known about the prognosis of cancer discovered during or after an episode of venous thromboembolism. METHODS: We linked the Danish National Registry of Patients, the Danish Cancer Registry, and the Danish Mortality Files to obtain data on the survival of patients who received a diagnosis of cancer at the same time as or after an episode of venous thromboembolism. Their survival was compared with that of patients with cancer who did not have venous thromboembolism (control patients), who were matched in terms of type of cancer, age, sex, and year of diagnosis. RESULTS: Of 668 patients who had cancer at the time of an episode of deep venous thromboembolism, 44.0 percent of those with data on the spread of disease (563 patients) had distant metastasis, as compared with 35.1 percent of 5371 control patients with data on spread (prevalence ratio, 1.26; 95 percent confidence interval, 1.13 to 1.40). In the group with cancer at the time of venous thromboembolism, the one-year survival rate was 12 percent, as compared with 36 percent in the control group (P<0.001), and the mortality ratio for the entire follow-up period was 2.20 (95 percent confidence interval, 2.05 to 2.40). Patients in whom cancer was diagnosed within one year after an episode of venous thromboembolism had a slightly increased risk of distant metastasis at the time of the diagnosis (prevalence ratio, 1.23 [95 percent confidence interval, 1.08 to 1.40]) and a relatively low rate of survival at one year (38 percent, vs. 47 percent in the control group; P<0.001). CONCLUSIONS: Cancer diagnosed at the same time as or within one year after an episode of venous thromboembolism is associated with an advanced stage of cancer and a poor prognosis.

Case-Control Studies↗
PubMed2000

Cancer risk and mortality in users of calcium channel blockers. A cohort study.

BACKGROUND: Data regarding the association between the use of calcium channel blockers and cancer risk have been conflicting. In the current study, the authors examined the cancer risk and mortality in users of calcium channel blockers in North Jutland County, Denmark. METHODS: The authors conducted a cohort study using record linkage between a population-based prescription database, the Danish Cancer Registry, and the Danish Death Registry including 23, 167 users of calcium channel blockers who received >/=2 prescriptions between January 1, 1989 and December 31, 1995. The authors calculated the standardized incidence ratios and standard mortality ratios for cancer, along with corresponding 95% confidence intervals (95% CI). RESULTS: Overall, 967 incident cases of cancer occurred, resulting in a standardized incidence ratio of 1.04 (95% CI, 0.98-1.11). There was a slightly elevated nonsignificant risk of tobacco-related cancer. No increased risk of breast or colon carcinoma was observed. The cancer mortality was close to that expected in the background population (standardized mortality ratio of 0.97; 95% CI, 0.89-1.04). CONCLUSIONS: This large-scale, population-based cohort study adds to the increasing evidence indicating no substantial association between the use of calcium channel blockers and the incidence rate of cancer or cancer mortality.

Adolescent↗
PubMed2000

Socioeconomic status, marital status and hip fracture risk: a population-based case-control study.

Socioeconomic status and social support have been identified as important determinants of several diseases and overall mortality, but these factors have not been adequately examined in relation to hip fracture risk. The aim of this study was to determine the relationship of socioeconomic status and marital status to hip fracture risk. We used data from a population-based case-control study in postmenopausal women aged 50-81 years during 1993-1995 who resided in six counties in Sweden. The analysis was based on 1327 incident cases of hip fracture and 3262 randomly selected controls. Socioeconomic and marital status were obtained by record linkage with census data in 1960, 1970, 1980 and 1990. Information on other possible risk factors for hip fracture was collected by a mailed questionnaire. Women who were gainfully employed in 1990 had an odds ratio (OR) of 0.74 [95% confidence interval (CI) 0.56-0.96] compared with those not gainfully employed; those in the highest tertile of household income had an OR of 0.74 (95% CI 0.60-0.90) compared with those in the lowest tertile of income. Women who lived in a one-family house had an OR of 0.85 (95% CI 0.72-0.99) compared with those living in an apartment. Divorced, widowed or unmarried women had a higher risk of hip fracture than married or cohabiting women; the OR was 1.40 (95% CI 1.06-1.85). Married women who were both gainfully employed and were living in a one-family house had a substantially decreased risk of hip fracture compared with unemployed women living without a partner in an apartment (OR 0.39; 95% CI 0.22-0.71). Occupational affiliation among women ever employed, and educational level, were not associated with hip fracture risk. We conclude that employment, household income, type of housing and marital status seem to be risk indicators of hip fracture risk independent of known osteoporotic risk factors.

Aged↗
PubMed2000

An introduction to epidemiological research with medical databases.

In most regards, database research is like any other epidemiological endeavor: excellent research can be conducted, but there are many potential difficulties. Training in appropriate epidemiological and statistical methodology, together with knowledge of the databases and their coding systems, is likely to magnify the advantages of databases and also minimize the potential problems. As in all epidemiological investigations, the quality of the data and the methodology employed need to be carefully considered in the context of the research questions at hand.

Databases, Factual↗
PubMed2000

Body size in different periods of life, diabetes mellitus, hypertension, and risk of postmenopausal endometrial cancer (Sweden).

OBJECTIVE: To measure the association between endometrial cancer risk and obesity at age 18 and recently, adult weight gain, diabetes mellitus and hypertension. METHODS: We performed a population-based, nationwide case-control study among postmenopausal women aged 50-74 years in Sweden, including 709 incident cases with histopathologically verified endometrial cancer and 3368 controls. RESULTS: Compared to lean women (recent body mass index (BMI), i.e. kg/m2 below 22.5), overweight women (recent BMI 28-29.99) had a 50% increase in risk for endometrial cancer (OR 1.5, 95% CI 1.0-2.1). Obese women (recent BMI 30-33.99) had a 3-fold increased risk (OR 2.9, 95% CI 2.0-4.0), and markedly obese women (recent BMI > or = 34) a 6-fold increased risk (OR 6.3, 95% CI 4.2-9.5). The OR for Type 2 diabetes mellitus was 1.5 (95% CI 1.0-2.1) and for Type 1 diabetes mellitus it was 13.3 (3.1-56.4). The effect of recent BMI was similar for tumors having different degrees of differentiation and myometrial invasion, and did not vary with age, time since menopause, smoking status, diabetes mellitus, and use of contraceptives. Hypertension increased risk only among obese women. BMI at age 18, height, and adult weight change were not independent risk factors. CONCLUSIONS: Recent overweight/obesity and diabetes mellitus (Types 1 and 2) are associated with endometrial cancer risk. Hypertension increases risk among obese women.

Adolescent↗
PubMed2000

Weight change and risk of postmenopausal breast cancer (United States).

OBJECTIVE: Although many studies have shown that higher weight increases the risk of postmenopausal breast cancer, some aspects of this association are unclear. In order to examine the risk associated with different patterns of weight change, we analyzed data from a large case-control study of postmenopausal breast cancer. METHODS: Participants included women aged 50 79 years (n = 5031) who are newly diagnosed with invasive breast cancer in Massachusetts, New Hampshire, and Wisconsin. Similarly-aged population controls (n = 5255) were selected at random from driver's license files and Medicare beneficiary lists. Height, weight, and information on other breast cancer risk factors were ascertained by structured telephone interviews from 1992 to 1995, and logistic regression was used to estimate multivariable-adjusted odds ratios (OR) and 95% confidence intervals (CI). RESULTS: Women in the top quintile groups for height at age 20, recent weight, and recent body mass index had significantly increased risks of breast cancer. Among women who reached their highest adult weight at younger ages (<45 years), increasing weight loss since that age was associated with a reduced risk of postmenopausal breast cancer (OR 0.90, CI 0.84 0.98, per 5 kg). However, weight loss among women whose highest weight occurred after age 45 was not associated with risk (OR 1.00, CI 0.95 1.05, per 5 kg). Weight gain since the lowest adult weight increased risk by 8% for each 5 kg of gain (OR 1.08, CI 1.06-1. 11). Temporary weight cycling (weight loss followed by weight gain) was not associated with increased risk. CONCLUSIONS: Weight gain clearly increased risk of postmenopausal breast cancer. These data lend further support to efforts aimed at helping women avoid weight gain as they age.

Aged↗
PubMed2000

Angiomatoid melanoma: a novel pattern of differentiation in invasive periocular desmoplastic malignant melanoma.

A case of locally invasive, long-standing desmoplastic and amelanotic malignant melanoma is described in an 84-year-old man. Histologic examination of the involved periorbital tissue showed neoplastic foci exhibiting a novel pattern reminiscent of microvascular proliferation. These regions were characterized by malignant, S-100-positive tumor cells lining vessel-like spaces in transverse sections and forming tubuler-like structures in longitudinal sections. Recent data indicate that melanoma cells may express genes and patterns of differentiation in vitro akin to endothelial cells. Because angiosarcoma often involves facial and scalp skin of elderly individuals, awareness of angiomatoid differentiation in melanoma has important diagnostic implications. HUM PATHOL 31:1520-1522.

Aged↗
PubMed2000

Estrogen receptor alpha gene polymorphisms and endometrial cancer risk.

Since the estrogen receptor alpha (ER) is an important mediator of hormonal responses such as proliferation in estrogen-sensitive tissues, we hypothesized that polymorphisms in the ER gene could be functional and associated with endometrial cancer risk. We performed a population-based case-control study in Sweden, focusing on restriction fragment length polymorphisms for XbaI and PvuII and an upstream TA repeat polymorphism. In the main analysis, 154 cases and 205 controls who never used hormone replacement therapy took part and we calculated age-adjusted and multivariate odds ratios (OR) and 95% confidence intervals (CI) using unconditional logistic regression. The XbaI X allele appeared to confer a reduced risk for endometrial cancer. The multivariate OR for the XX genotype was 0.52 (95% CI 0.21-1.29) compared to the xx genotype and there were suggestions of decreasing risk with increasing number of X alleles (P for trend = 0.07). The PvuII PP genotype was also associated with a non-significantly decreased risk for endometrial cancer (multivariate OR 0.70, 95% CI 0.34-1.44) compared with the pp genotype (P for trend = 0.43). The multivariate OR for two short TA (<19 repeats) alleles versus two long alleles was 1.54 (95% CI 0. 73-3.27) and there were suggestions of increasing risk with increasing number of short alleles (P for trend = 0.26). We observed the same pattern of results in an expanded group of subjects, which included women who had used hormone replacement (in total 288 cases and 392 controls). Our data suggest that variants of the ER gene may be associated with an altered risk of endometrial cancer.

Aged↗
PubMed2000

Physical activity and hip fracture: a population-based case-control study. Swedish Hip Fracture Study Group.

BACKGROUND: A growing body of literature suggests that physical activity may be a protective factor against hip fracture. METHODS: To study the association between hip fracture risk and recreational physical activity at various ages, changes in activity during adult life, occupational physical activity and how risks vary by adult weight change, we performed a population-based case-control study among postmenopausal women aged 50-81 years residing in six counties in Sweden in 1993-1995. The analysis consisted of 1327 women with hip fracture and 3262 randomly selected controls. Information on leisure physical activity before age 18, at 18-30 years and during recent years was based on a questionnaire. Data on occupational physical activity were collected through an independent classification of job titles obtained from record linkage with census data from 1960, 1970 and 1980. RESULTS: There was a protective effect of recent leisure physical activity. Compared to women who reported no leisure activity, the odds ratios (OR) were 0.79 (95% CI: 0.62-1.00), 0.67 (95% CI: 0.54-0.84) and 0.48 (95% CI: 0.39-0.60) for women who exercised <1 h per week, 1-2 h per week, and 3+ h per week, respectively. These decreased OR were more pronounced in women who had lost weight after 18 years of age than in those who had gained weight. Women with high physical activity at both 18-30 years and during recent years did not have a stronger protection than those with isolated high activity late in life, after accounting for recent activity. Occupational physical activity was not associated with hip fracture risk in this study. CONCLUSIONS: Recent physical activity is protective against hip fracture. The protective effect is most pronounced in women who had lost weight after age 18.

Aged↗
PubMed2000

Left-handedness in relation to breast cancer risk in postmenopausal women.

Breast cancer risk may be influenced by intrauterine exposure to steroid hormones. We evaluated left-handedness, a marker of intrauterine hormone exposure, in relation to breast cancer risk in our population-based, case-control study. Case women 50-79 years of age with a first diagnosis of invasive breast cancer were ascertained through statewide cancer registries in Wisconsin, Massachusetts, and New Hampshire. Control women were identified in each state through lists of licensed drivers (for ages 50-64) and Medicare beneficiaries (for ages 65-79), and selected at random to correspond with the age distribution of case women. Exposure information, including handedness, was obtained through a telephone interview. Our results indicated a modest association between left-handedness and breast cancer risk (OR = 1.42; 95% CI = 1.10-1.83). The effect of left-handedness was modified by age; we observed the greatest risk ratio in the oldest age group. Left-handedness was not associated with breast tumor laterality. Our results are consistent with the hypothesis that intrauterine hormone exposures play a role in the development of breast cancer.

Aged↗
PubMed2000

Body size and hip fracture risk. Swedish Hip Fracture Study Group.

The objective of this population-based case-control study was to determine the independent association between height, weight at different ages and adult weight change on hip fracture risk, and the joint effects of these factors. The study base comprised postmenopausal women 50-81 years of age who resided in six counties in Sweden during the period October 1993 to February 1995. The study included 1,327 cases with an incident hip fracture and 3,262 randomly selected controls. We obtained information on body measures and other factors possibly related to hip fracture through mailed questionnaires and telephone interviews. Height and weight change were dominant risk factors. Tall women (> or = 169 cm) had an odds ratio of 3.16 (95% confidence interval = 2.47-4.05) compared with women shorter than 159 cm. Weight gain during adult life was strongly protective: compared with those with moderate weight change (-3 to 3 kg), those with substantial weight gain (> or =12 kg) had a markedly decreased risk of hip fracture (odds ratio = 0.35; 95% confidence interval = 0.27-0.45), whereas weight loss was associated with an increased risk. Weight change retained important effects among all subjects, even after controlling for current weight and weight at age 18. In contrast, among women who gained weight, the separate effects of current weight and weight at age 18 were small or absent. Among women who lost weight, both current weight and weight at age 18 had effects that remained after controlling for weight change. Adult weight change and height are dominant body size risk factors for hip fracture. Weight loss vs weight changes demarcates different patterns of hip fracture risk.

Age Distribution↗
PubMed2000

Nonsteroidal anti-inflammatory drugs and cancer prevention.

Nonsteroidal anti-inflammatory drugs (NSAIDs), including aspirin, appear to have clinically significant anticarcinogenic effects in the gastrointestinal tract. Epidemiological data indicate that use of these drugs is inversely associated with the risk of sporadic colorectal cancer, and clinical trials among patients with familial polyposis coli show that NSAIDs can lead to the regression of large bowel adenomas. Animal studies have reported a similar efficacy of NSAIDs against experimental carcinogenesis. A consistent pattern in this research is that continued long-term use of NSAIDs is required for an anticancer effect--up to 15 or 20 years before a reduced risk of colorectal cancer appears. Epidemiological data also suggest possible protective effects in the stomach and esophagus. The mechanisms underlying any chemopreventive effect of NSAIDs are not clear. Inhibition of cyclooxygenase is one possibility, but pathways independent of cyclooxygenase and prostaglandins are also possible.

Adenoma↗
PubMed2000

Organochlorines and endometrial cancer risk.

There is concern that persistent environmental pollutants such as dichlorodiphenyltrichloroethane (DDT) and polychlorinated biphenyls (PCBs) increase breast cancer risk, at least partially through estrogenic effects. Because the endometrium is more sensitive to estrogenic stimulation than the breast, such a carcinogenic effect should be more pronounced in the endometrium than the breast. In a population-based case-control study in Sweden, we measured serum concentrations of 10 chlorinated pesticides and 10 PCB congeners in 154 endometrial cancer cases and 205 population controls. Information on potential confounders was obtained by mailed questionnaires. We used logistic regression to calculate odds ratios (ORs) as measures of relative risk. We performed analyses for lipid-adjusted concentrations of each individual substance and after grouping substances according to putative hormonal effects. We found no significant associations of increasing levels of pesticide or PCB exposure with endometrial cancer risk. The multivariate OR was 1.0 (95% confidence interval, 0.6-2.0; P for trend, 0.78) for the highest compared with the lowest quartile of dichlorodiphenyldichloroethylene (DDE), the predominant dichlorodiphenyltrichloroethane metabolite. Corresponding ORs were 1.0 for hexachlorobenzene, 0.9 for beta-hexachlorocyclohexane, 1.4 for oxychlordane, and 1.2 for trans-nonachlor. Analyses of substances grouped by putative hormonal effect also showed no associations with endometrial cancer risk. For all estrogenic compounds, the OR for the highest compared with the lowest quartile was 1.1 (95% confidence interval, 0.6-2.2; P for trend, 0.90). Our data do not support the hypothesis that the organochlorine exposure studied increases the risk for endometrial cancer.

Aged↗
PubMed2000

Serum ferritin concentration and recurrence of colorectal adenoma.

Both body iron stores and dietary iron intake have been reported to increase risk of colorectal neoplasms. We assessed whether serum ferritin concentration was associated with recurrence of colorectal adenomas among 733 individuals with baseline determinations of ferritin as part of a multicenter clinical trial of antioxidant supplements for adenoma prevention. All study participants had at least one adenoma removed within 3 months before enrollment, and 269 of them developed one or more adenomas between follow-up colonoscopies conducted 1 and 4 years after enrollment. Baseline serum ferritin concentrations were analyzed both as a log-transformed continuous variable and as a categorical variable, defined as whether iron stores were nonreplete and low (ferritin < or =30 microg/liter), nonreplete and borderline (31-70 microg/liter), replete and adequate (71-160 microg/liter), or replete and high (>160 microg/liter). Analyses were based on multiple logistic regression models, including age, sex, study center, energy, alcohol, fiber, folate, and total fat intake, number of months between colonoscopic examinations, smoking status, and aspirin use. Overall, there was no statistically significant linear association between log ferritin concentration and adenoma recurrence (P = 0.33). Risk of adenoma recurrence was modestly increased among participants with ferritin concentrations >70 microg/liter relative to those with lower ferritin (odds ratio, 1.39; 95% confidence interval, 0.96-2.02). This result seemed more pronounced among women than men. Dietary intake of iron and red meat was inversely associated with adenoma recurrence among participants with replete iron stores but not consistently associated among those with nonreplete stores. Our findings suggest that any role of iron stores and dietary iron in influencing risk of colorectal adenoma recurrence is likely complex.

Adenoma↗
PubMed2000

Rectal mucosal proliferation and risk of colorectal adenomas: results from a randomized controlled trial.

Although rectal mucosal labeling index is thought to be a useful surrogate biomarker for colorectal cancer, the ability of the index to predict future neoplasia is unclear. We obtained rectal mucosal biopsies from 333 participants of a randomized controlled chemoprevention trial of calcium supplementation to determine whether labeling index was correlated with concurrent or future colorectal neoplasms. Labeling index was measured using proliferating cell nuclear antigen immunohistochemistry. Adenomas were enumerated at the time of the biopsies (cross-sectional) and 3 years later (prospective). We used logistic regression to test for an association of adenoma occurrence with overall labeling index, the mean proliferative height, and labeling index in the upper 40% of colon crypts. In the cross-sectional analysis, we found indications that higher proliferation was associated with an increase in the prevalence of adenomas. The overall adjusted odds ratios (OR) (95% confidence interval) were 1.14 (0.90-1.45) per % crypt labeling index, OR 1.08 (0.99-1.19) for upper crypt proliferation, and OR 1.07 (1.03-1.12) for proliferative height. In contrast, individuals with higher labeling index at baseline were actually less likely to have adenomas in the prospective analyses: OR 0.80 (0.62-1.02) per % crypt labeling index, OR 0.86 (0.73-1.00) for upper crypt index, and OR 0.97 (0.93-1.01) for proliferative height. Proliferative index does not predict future colorectal neoplasia, although it may be weakly associated with the presence of current adenomas. These results have important implications for the design of future intervention studies. Although it may be attractive to include the measurement of intermediate markers in large controlled trials, until we have more confidence in their performance, we should rely on better proven and more reliable intermediates, such as adenomas.

Adenoma↗