Search PubMed⌕ Search

SEARCH · Search PubMed

Results for “Logistic Model”

Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 1,153 records · Page 64Linked to original sources
PubMed2002

Interactions between genetic and reproductive factors in breast cancer risk in a population-based sample of African-American families.

Incidence of breast cancer (BC) varies among ethnic groups, with higher rates in white than in African-American women. Until now, most epidemiological and genetic studies have been carried out in white women. To investigate whether interactions between genetic and reproductive risk factors may explain part of the ethnic disparity in BC incidence, a genetic epidemiology study was conducted, between 1989 and 1994, at the Howard University Cancer Center (Washington, DC), which led to the recruitment of 245 African-American families. Segregation analysis of BC was performed by use of the class D regressive logistic model that allows for censored data to account for a variable age of onset of disease, as implemented in the REGRESS program. Segregation analysis of BC was consistent with a putative dominant gene effect (P < 0.000001) and residual sister-dependence (P < 0.0001). This putative gene was found to interact significantly with age at menarche (P = 0.048), and an interaction with a history of spontaneous abortions was suggested (P = 0.08). A late age at menarche increased BC risk in gene carriers but had a protective effect in non-gene carriers. A history of spontaneous abortions had a protective effect in gene carriers and increased BC risk in non-gene carriers. Our findings agree partially with a similar analysis of French families showing a significant gene x parity interaction and a suggestive gene x age at menarche interaction. Investigating gene x risk factor interactions in different populations may have important implications for further biological investigations and for BC risk assessment.

Abortion, Spontaneous↗
PubMed2005

Drinking patterns are associated with variations in atherosclerotic risk factors in French men.

BACKGROUND: While a relationship between alcohol and cardiovascular risk factors is well established, data suggest that the type of alcoholic beverage could modulate this relationship. AIM OF THE STUDY: To determine whether drinking patterns modulate the relationship between alcohol and cardiovascular risk factors. METHODS: We tested the relationship between preference of alcoholic beverages and atherosclerotic risk factors in a cross-sectional study of 2,126 men. A hierarchical clustering method determined six drinking patterns, 'low drinkers', 'high quality wines', 'beer and cider', 'digestives', 'local wines', and 'table wines', according to the preferential intake of alcoholic beverages. Logistic models estimated the relative risk of abnormal markers in the drinking patterns compared with low drinkers. Unadjusted estimates investigated the relationship with the cluster as a group, while adjustment on alcohol, nutritional and socio-demographic factors investigated the relationship with the preference of alcoholic beverage in itself. RESULTS: Abstainers had high total plasma homocysteine (tHcy), even after full adjustment (odds ratio (OR) = 1.6, 95% confidence interval (CI): 1.0, 2.8). Drinkers of high quality wine had low lipoprotein( a), high tHcy and high body mass index; beer and cider drinkers had high tHcy and waist circumference. Drinkers of digestives had high triacylglycerol; after adjustment they were at risk of low apolipoprotein A-I (OR = 3.1, 95% CI: 1.2, 7.3), and high tHcy (OR = 4.9, 95% CI: 1.2, 33.3). Local wines drinkers were similar to low drinkers. Table wine drinkers had high apolipoprotein B, high triacylglycerol, and high waist-to-hip ratio. CONCLUSION: Our data suggest that preference of alcoholic beverage could indicate groups at specific risks of atherosclerotic disease.

Alcohol Drinking↗
PubMed2002

Smoking and mortality following acute myocardial infarction: results from the National Registry of Myocardial Infarction 2 (NRMI 2).

BACKGROUND: Current smokers have lower mortality following acute myocardial infarction (AMI) than non-smokers. This is often referred to as the "smokers' paradox". Our study explored possible explanations of this phenomenon. METHODS: From the 510,044 cases of AMI in the NRMI 2 from 1 June 1994, through 30 April 1997, 297,458 cases without hospital transfer were analyzed. Characteristics and treatments of tobacco smokers and non-smokers were compared before and after age-standardization. Multivariate logistic models investigated possible associations with in-hospital mortality using clinically relevant variables and interaction terms. RESULTS: Twenty-four per cent of AMI cases were current smokers. Smokers were 14 years younger than non-smokers (mean age 58 vs. 72 years, p<0.001) and had lower in-hospital mortality (8.0% vs. 16.4%, p<0.001). After age-standardization, smokers were more likely than non-smokers to suffer a Q-wave type of infarction, and were less likely to have a prior history of diabetes, hypertension, AMI, angina, cardiac failure, and coronary interventions. The unadjusted odds ratio (OR) for smoking and mortality was 0.44 (95% confidence interval, CI 0.43-0.45). After adjustment for age the OR was 0.81 (95% CI 0.78-0.83). Additional adjustment for previous medical history/cardiovascular risk factors changed the OR to 0.86 (95% CI 0.83-0.89). Adjustment for additional covariates and interaction terms had little effect. CONCLUSIONS: Smokers with AMI were on average 14 years younger than non-smokers, explaining most of the apparent association of smoking with differences in presentation and treatment, and lower in-hospital mortality. The residual association of smoking and better prognosis, the "smoker's paradox", was not fully explained by measured covariates.

Aged↗
PubMed1996

Severity measurement methods and judging hospital death rates for pneumonia.

Payers and policymakers are increasingly examining hospital mortality rates as indicators of hospital quality. To be meaningful, these death rates must be adjusted for patient severity. This research examined whether judgments about an individual hospital's risk-adjusted mortality is affected by the severity adjustment method. Data came from 105 acute care hospitals nationwide that use the Medis-Groups severity measure. The study population was 18,016 adults hospitalized in 1991 for pneumonia. Multivariable logistic models to predict in-hospital death were computed separately for 14 severity methods, controlling for patient age, sex, and diagnosis-related group (DRG). For each hospital, observed-to-expected death rates and z scores were calculated for each severity method. The overall in-hospital death rate was 9.6%. Unadjusted mortality rates for the 105 hospitals ranged from 1.4% to 19.6%. After adjusting for age, sex, DRG, and severity, 73 facilities had observed mortality rates that did not differ significantly from expected rates according to all 14 severity methods; two had rates significantly higher than expected for all 14 severity methods. For 30 hospitals, observed mortality rates differed significantly from expected rates when judged by one or more but not all 14 severity methods. Kappa analysis showed fair to excellent agreement between severity methods. The 14 severity methods agreed about relative hospital performance more often than expected by chance, but perceptions of individual hospitals' mortality rates varied using different severity adjustment methods for almost one third of facilities. Judgments about individual hospital performance using different severity adjustment approaches may reach different conclusions.

Adolescent↗
PubMed2002

Relation of Helicobacter pylori infection and lifestyle to the risk of chronic atrophic gastritis: a cross-sectional study in Japan.

To examine the mutual association of risk factors for both Helicobacter pylori (H. pylori) infection and chronic atrophic gastritis (CAG), a cross-sectional study on 954 residents of a rural town in Japan was conducted. Using an unconditional logistic model, we calculated the odds ratios (ORs) for H. pylori infection according to each lifestyle, as well as the ORs for CAG according to each lifestyle and H. pylori infection. A significant positive association was observed between H. pylori infection and the risk of CAG (OR = 6.29). On the other hand, a significant negative association was observed between high consumption of light-colored vegetables and the risk of CAG (OR = 0.68). We also used a path analysis to examine the direct relations of gender, age, and lifestyle variables to CAG, as well as the indirect relations of these variables to CAG through H. pylori infection. Aging had a significantly direct positive association with CAG. Although aging also had an indirect positive association with CAG through H. pylori infection, aging had no association with the consumption of light-colored vegetables. The high consumption of light-colored vegetables showed no association with H. pylori infection but had a significantly direct negative association with CAG. The results of this study suggest a possibility that high light-colored vegetables consumption contributes to the prevention of CAG.

Adult↗
PubMedDate not supplied

Multistate modelling of liver transplantation data.

This paper concerns the survival analysis of liver transplant patients when patients with a potentially fatal rejection of the transplanted organ may receive a retransplant. A multistate model, analysing the states 'alive with first graft' and 'alive with second graft' separately, is suggested. Proportional hazards models and logistic regression models are used to evaluate which risk factors related to donor, preservation and recipient, influence the transition intensities. The complete model is used to predict overall survival of a patient and to study the influence of the risk factors on total survival.

Adolescent↗
PubMed1997

Relative weight and mortality in U.S. blacks and whites: findings from representative national population samples.

PURPOSE: To examine the impact of relative weight on mortality in black and white men and women. METHODS: Two representative national populations samples were used: the NHANES-I Epidemiologic Follow-up Study (NHEFS), and the National Health Interview Survey (NHIS). The principal analysis focused on 13,242 participants in the NHEFS and 114,954 in the NHIS. Minimum mortality was estimated from both categorical analysis and a logistic model. RESULTS: Minimum mortality ranged from a body mass index (BMI) of 25 to 32 kg/m2. The model-estimated BMI of minimum mortality for NHEFS was 27.1 (24.8-29.4, 95% CI), 26.8 (24.7-28.9, 95% CI), 24.8 (23.8-25.9, 95% CI) and 24.3 (23.2-25.4, 95% CI); for black men, black women, white men and white women, respectively, whereas for NHIS the corresponding values were 30.2 (24.8-35.6, 95% CI) 26.4 (24.2-28.7, 95% CI), 27.1 (25.5-28.7, 95% CI), and 25.6 (24.2-27.0, 95% CI). In all groups the shape of the relative risk curve was virtually identical and a broad range of BMI values in the middle of the distribution was associated with low relative mortality risk. Averaging the results from both surveys, the observed BMI of minimum risk was 3.1 kg/m2 higher in black men and 1.5 kg/m2 higher in black women than in their white counterparts; when adjusted for covariates these differences were only of borderline statistical significance, however. CONCLUSIONS: Because of the wide range of BMI values associated with low risk, and the consistency of the point of the up-turn in risk, group specific definitions of optimal values do not appear to be warranted.

Adult↗
PubMed2006

Distributions of mortality risk attributable to low nutritional status in Niakhar, Senegal.

This study proposes a method for computing the distributions of mortality risk attributable to malnutrition among children of developing countries. Population distributions of nutritional status were adjusted with a normal curve and the relation between mortality and nutritional status was fitted with a linear logistic model after controlling for age. The attributable risk for mortality could therefore be computed at any threshold of low nutritional status. The method was applied in Niakhar, Senegal, where a comprehensive study of the relation between nutritional status and mortality was conducted in 1983-1984 on approximately 5,000 children, 6-59 mo of age. The anthropometric indicators used were Z-scores of weight-for-age, weight-for-height, height-for-age, head circumference-for-age, arm circumference-for-age, triceps skinfold-for-age, and subscapular skinfold-for-age, plus arm circumference, body mass index, and 2 composite indicators. Population attributable fraction varied according to indicators selected and ranged from 31% (head circumference) to 65% (arm circumference). The 2 composite indicators summarizing the whole nutritional status provided the same value for the population attributable fraction (59 and 60%, respectively). Classic thresholds of mild, moderate, and severe malnutrition are presented, as well as the bivariate distribution of wasting and stunting. Whatever the indicator used, mortality attributable risks appeared evenly distributed along the scale of low nutritional status. Our findings question the value of using classic thresholds of mild, moderate, and severe malnutrition (developed by clinicians for practical purposes) for nutritional epidemiology.

Child, Preschool↗
PubMedDate not supplied

Molecular response of follicular lymphoma to cyclophosphamide, doxorubicin, vincristine, prednisone C(H)OP or COP-based therapy as measured by polymerase chain reaction evidence of translocation (14;18)(q32;q21).

PURPOSE: Existing data suggest that conventional C(H)OP (cyclophosphamide, doxorubicin, vincristine, prednisone) regimen may not be intensive enough to achieve molecular response, as measured by polymerase chain reaction (PCR) evidence of translocation (14;18)(q32:q21) for follicular lymphoma. This study was undertaken to study the molecular response rate of follicular lymphoma to C(H)OP-based therapy and to analyze prognostic factors for molecular response. PATIENTS AND METHODS: Twenty patients with pretreatment PCR evidence of t(14;18)(q32; q21) and at least one posttreatment PCR analysis after the initiation of the treatment with C(H)OP with or without radiation therapy constituted the basis for this analysis. The random effects logistic model was used to analyze the data. The following factors were investigated for their relationship to molecular response: gender, age, beta2-microglobulin, use of radiation therapy, Ann Arbor stage, and international Prognostic Index for malignant lymphoma. RESULTS: Median follow-up was 56 months (range, 23-153 months). A total of 135 PCR results were available, 33 from bone marrow and 102 from peripheral blood. Overall, there was a clear and steady decreasing trend toward loss of PCR positivity with increasing time aftertreatment. By univariate analysis, stage > or = 3, stage = 4, International Prognostic Index > or = 2, and no radiation therapy were adverse factors for molecular response. On multivariate analysis, Ann Arbor stage IV and no radiation therapy were independent risk factors for PCR positivity, both for the peripheral blood data analyzed alone and for all data combined. DISCUSSION: It is possible to achieve molecular response with C(H)OP with or without radiation therapy in patients with follicular lymphoma. Response rate depends on the Ann Arbor stage and radiation therapy.

Adult↗
PubMed2006

Factors associated with adolescents' physical inactivity in Xi'an City, China.

PURPOSE: To explore the sociodemographic and environmental factors at community, school, and household levels associated with physical inactivity. METHODS: In a cross-sectional study in 2004, physical activity level was assessed using a validated questionnaire in 1787 students. Physical inactivity was defined as less than 150 min.wk of moderate activity (4-6 METs) or less than 60 min.wk of vigorous activity (> 6 METs). Sociodemographic and environmental information was recorded on self-administered questionnaires. Hierarchical multiple logistic models were developed based on a conceptual framework of factors related to physical activity. RESULTS: Overall, girls were twice as likely to be inactive. Adolescents aged 14 yr were 30% less likely to be inactive compared with those younger than 13 yr (95% CI: 0.5-0.9). Paternal education was inversely associated with inactivity (OR: 0.6, 95% CI: 0.4-0.9). Adolescents living in neighborhoods without sidewalks were 1.3 times more likely to be inactive (95% CI: 1.0-1.6). At the school level, lack of extracurricular exercise (OR: 1.3, 95% CI: 1.1-1.6) and fewer sports meetings (OR: 2.0, 95% CI: 1.4-2.9) were associated with physical inactivity. Difficult access to community recreational facilities (moderate OR: 1.4, 95% CI: 1.0-1.9; difficult OR: 1.7, 95% CI: 1.2-2.4) and concerns about safety in the neighborhood (OR: 2.1, 95% CI: 1.1-4.1) were associated with inactivity. There were some differences associated with physical inactivity between boys and girls. CONCLUSION: Strategies to promote physical activity in Chinese adolescents should integrate associated factors at household, school, and community levels and address the important gender differences in factors associated with physical inactivity in youth.

Adolescent↗
PubMed1994

On the relationship between nausea and vomiting in patients undergoing chemotherapy. Italian Group for Antiemetic Research.

In comparative trials on antiemetic efficacy of different regimens, the positive correlation between the probabilities of vomiting and of nausea could hide some confounding effect. Our work seeks to detect such effects. The data from two large studies on prevention of cisplatin-induced emesis were re-analyzed using two multifactorial logistic models. The first study compared ondansetron + dexamethasone (Ond+Dex) with metoclopramide+dexamethasone+diphenhydramine (Mtc+Dex+Dip), the second compared Mtc+Dex+Dip with Mtc+prednisolone. A group of 267 patients in the first study and 343 in the second, all evaluable for clinical efficacy, were followed for three subsequent cycles of chemotherapy. The antiemetic regimen administered and the complete protection from acute vomiting and nausea were recorded. In the first study (cycle 1), after adjustment for the presence/absence of vomiting, the two therapies were no longer found significantly different on complete protection from nausea: the greater efficacy of Ond+Dex in preventing nausea was due to a confounding effect. Instead, in the second study, the greater efficacy of Mtc/Dex/Dip in preventing both nausea and vomiting was confirmed. The results indicate that, when a correlation between two responses is detected, multifactorial analyses should be performed to identify the possible presence of some confounding effect. The proof that the presence/absence of vomiting is a confounding factor for the relationship between the different efficacy of the two antiemetic regimens for complete protection from nausea, highlighting the same efficacy of the two therapies in preventing nausea, supports the hypothesis of the existence of two kinds of nausea, one independent of vomiting, the other concomitant with it.

Antiemetics↗
PubMed2003

The association between lower urinary tract symptoms and erectile dysfunction in four centres: the UrEpik study.

OBJECTIVE: To report a large-scale multinational investigation of lower urinary tract symptoms (LUTS) and sexual function, designed to investigate the independent association between them, as recent small-scale epidemiological studies suggest an association between benign prostatic hyperplasia and sexual dysfunction; both conditions are strongly associated with age and no study has been able to exclude age as a confounding factor in this relationship. SUBJECTS AND METHODS: Culturally and linguistically validated versions of standard questionnaires were used to estimate the prevalence of LUTS (using the International Prostate Symptom Score, IPSS) and erectile dysfunction (ED) score (using O'Leary's Sexual Function Inventory) in regions of the UK (Birmingham), the Netherlands (Boxmeer), France (Auxerre) and Korea (Seoul). In each centre, stratified random samples were selected from population registers to provide representative samples of the population of men aged 40-79 years (and their partners) in each community. Direct interviews were held in Seoul and postal questionnaires used in the three European centres. The samples were selected randomly, providing representative samples in each community. RESULTS: In all, 4800 men and 3674 women responded; the response rates among men were 77% in Boxmeer, 21% in Auxerre, 42% in Birmingham and 65% in Seoul. The overall prevalence of ED for men aged 40-79, estimated as an ED score of 0-4, was 21.1%. There was evidence of a linear increase with age (P < 0.001) and the pattern was very similar in the four centres. From the weighted logistic model, there was evidence of an association between sexual dysfunction, other self-reported diseases and lifestyle. From the ED score, after adjusting for age and country, men with diabetes were more likely to score of 0-4 (odds ratio 1.57, 95% confidence interval 1.09-2.25), as were those with high blood pressure (1.38, 1.09-1.75) and with an IPSS of 8-35 (1.39, 1.10-1.74). For lifestyle, smokers were more likely to score 0-4 (1.54, 1.23-1.92), while physical activity during leisure time was slightly associated with a reduction in the chance of scoring 0-4 (0.87, 0.77-0.99). The analysis gave the same results when repeated using self-reported ED instead of the dichotomised score. CONCLUSIONS: ED is clearly age-related and a problem for a large proportion of men in the community. It can have a profound impact on the quality of life of the man and on his partner. Were all men with this problem to seek medical help there would be a large burden on healthcare systems. There are cultural and age effects on the assessment of this problem.

Adult↗
PubMed2005

Dietary fiber intake and risk factors for cardiovascular disease in French adults.

BACKGROUND: Increased consumption of dietary fiber is widely recommended to maintain or improve health, but knowledge of the relation between dietary fiber sources and cardiovascular disease risk factors is limited. OBJECTIVE: We examined the relation between the source or type of dietary fiber intake and cardiovascular disease risk factors in a cohort of adult men and women. DESIGN: In a cross-sectional study, quintiles of fiber intake were determined from dietary records, separately for 2532 men and 3429 women. Age- and multivariate-controlled logistic models investigated the odds ratios of abnormal markers for quintiles 2-5 of fiber intake compared with the lowest quintile. RESULTS: The highest total dietary fiber and nonsoluble dietary fiber intakes were associated with a significantly (P < 0.05) lower risk of overweight and elevated waist-to-hip ratio, blood pressure, plasma apolipoprotein (apo) B, apo B:apo A-I, cholesterol, triacylglycerols, and homocysteine. Soluble dietary fiber was less effective. Fiber from cereals was associated with a lower body mass index, blood pressure, and homocysteine concentration; fiber from vegetables with a lower blood pressure and homocysteine concentration; and fiber from fruit with a lower waist-to-hip ratio and blood pressure. Fiber from dried fruit or nuts and seeds was associated with a lower body mass index, waist-to-hip ratio, and fasting apo B and glucose concentrations. Fiber from pulses had no specific effect. CONCLUSION: Dietary fiber intake is inversely correlated with several cardiovascular disease risk factors in both sexes, which supports its protective role against cardiovascular disease and recommendations for its increased consumption.

Adult↗
PubMed2005

Perioperative beta-blocker therapy and mortality after major noncardiac surgery.

BACKGROUND: Despite limited evidence from randomized trials, perioperative treatment with beta-blockers is now widely advocated. We assessed the use of perioperative beta-blockers and their association with in-hospital mortality in routine clinical practice. METHODS: We conducted a retrospective cohort study of patients 18 years of age or older who underwent major noncardiac surgery in 2000 and 2001 at 329 hospitals throughout the United States. We used propensity-score matching to adjust for differences between patients who received perioperative beta-blockers and those who did not receive such therapy and compared in-hospital mortality using multivariable logistic modeling. RESULTS: Of 782,969 patients, 663,635 (85 percent) had no recorded contraindications to beta-blockers, 122,338 of whom (18 percent) received such treatment during the first two hospital days, including 14 percent of patients with a Revised Cardiac Risk Index (RCRI) score of 0 and 44 percent with a score of 4 or higher. The relationship between perioperative beta-blocker treatment and the risk of death varied directly with cardiac risk; among the 580,665 patients with an RCRI score of 0 or 1, treatment was associated with no benefit and possible harm, whereas among the patients with an RCRI score of 2, 3, or 4 or more, the adjusted odds ratios for death in the hospital were 0.88 (95 percent confidence interval, 0.80 to 0.98), 0.71 (95 percent confidence interval, 0.63 to 0.80), and 0.58 (95 percent confidence interval, 0.50 to 0.67), respectively. CONCLUSIONS: Perioperative beta-blocker therapy is associated with a reduced risk of in-hospital death among high-risk, but not low-risk, patients undergoing major noncardiac surgery. Patient safety may be enhanced by increasing the use of beta-blockers in high-risk patients.

Adrenergic beta-Antagonists↗
PubMed2004

Impact of HAART-related side effects on unsafe sexual behaviours in HIV-infected injecting drug users: 7-year follow up.

OBJECTIVE: To investigate the impact of non-lipodystrophy HAART-related side effects on unprotected sexual behaviours among HIV-infected drug users. DESIGNAND PARTICIPANTS: HAART-treated patients who reported having occasional partners during the follow-up period after HAART initiation were selected among patients of the MANIF 2000 cohort of HIV-infected drug users. METHODS: Visits where patients reported unsafe sexual behaviours with occasional partners were compared to visits where they reported safe sexual behaviours using a logistic model based on Generalized Estimating Equations. RESULTS: One-hundred and ninety-two HAART-treated patients reported occasional sexual partners at least once during follow-up, accounting for a total of 464 visits. Among these 192 patients, 134 (70%) declared at least once unsafe sexual behaviours with occasional partners. During follow-up, three or more HAART-related side effects were reported in 273 of the 464 visits. When comparing visits where patients reported unsafe sexual behaviours with occasional partners (n = 249) with those where they reported safe sexual behaviours (n = 215), experiencing three or more HAART-related side effects was significantly associated with unsafe sex after adjustment for cofactors such as injecting drug status, reporting more than two sexual partners and having sex more than once a week. CONCLUSIONS: Perceived side effects play a role in determining unsafe sexual behaviours. HIV prevention interventions must consider the negative impact of HAART-related side effects on sexual risk-taking behaviours. Drug maintenance programs contribute to sexual risk reduction among drug injecting patients.

Adult↗
PubMed2006

Case-control geographic clustering for residential histories accounting for risk factors and covariates.

BACKGROUND: Methods for analyzing space-time variation in risk in case-control studies typically ignore residential mobility. We develop an approach for analyzing case-control data for mobile individuals and apply it to study bladder cancer in 11 counties in southeastern Michigan. At this time data collection is incomplete and no inferences should be drawn - we analyze these data to demonstrate the novel methods. Global, local and focused clustering of residential histories for 219 cases and 437 controls is quantified using time-dependent nearest neighbor relationships. Business address histories for 268 industries that release known or suspected bladder cancer carcinogens are analyzed. A logistic model accounting for smoking, gender, age, race and education specifies the probability of being a case, and is incorporated into the cluster randomization procedures. Sensitivity of clustering to definition of the proximity metric is assessed for 1 to 75 k nearest neighbors. RESULTS: Global clustering is partly explained by the covariates but remains statistically significant at 12 of the 14 levels of k considered. After accounting for the covariates 26 Local clusters are found in Lapeer, Ingham, Oakland and Jackson counties, with the clusters in Ingham and Oakland counties appearing in 1950 and persisting to the present. Statistically significant focused clusters are found about the business address histories of 22 industries located in Oakland (19 clusters), Ingham (2) and Jackson (1) counties. Clusters in central and southeastern Oakland County appear in the 1930's and persist to the present day. CONCLUSION: These methods provide a systematic approach for evaluating a series of increasingly realistic alternative hypotheses regarding the sources of excess risk. So long as selection of cases and controls is population-based and not geographically biased, these tools can provide insights into geographic risk factors that were not specifically assessed in the case-control study design.

Age Factors↗
PubMed2006

Statistical methods of estimating fracture risk.

The aim of the article is to present an analysis of statistical methods used for estimating fracture risk in patients with osteoporosis. Mathematical relations of different methods are explained (risk--R, risk ratio--RR, RD--risk difference, odds--O, odds ratio--OR, Yule's Q, Yule's Y, logistic model). What is important to keep in mind is that: 1) relative risk and odds ratio are statistics that only describe an association, not causation; 2) relative risk and odds ratio refer to a population, not to an individual patient; 3) the studies of small groups are more likely to find an association that might actually just be due to chance, the larger the groups, the less likely the association between a risk factor and an outcome (fracture); 4) when the incidence of an outcome of interest in the study population is low (<10 %), the OR is close to the RR, the more frequent the outcome becomes, the more the OR will overestimate the RR when it is more than 1 or underestimate the RR when it is less than 1. Sophisticated statistical packages are available which can calculate many of the tests of association but the problem is that the investigator must know which is the desirable one. The incorrect option of statistical analysis, the incorrect interpretation of risk ratio or odds ratio and overestimation of the importance of a risk factor may lead to unintentional errors in the economic analysis of potential programs or treatments in osteoporosis. This article could be a contribution for investigators who are concerned with assessment of fracture risk.

Age Factors↗