Biomedical subjects

Murray A Mittleman

Publications and source records attributed to Murray A Mittleman.

At least 19 recordsLinked to original sources

PubMed2007

Prevalent rheumatoid arthritis and diabetes among NHANES III participants aged 60 and older.

OBJECTIVE: This study examines the cross-sectional association between prevalent rheumatoid arthritis (RA) and diabetes among noninstitutionalized US civilians aged >or= 60 years between 1988 and 1994. METHODS: Using National Health and Nutrition Examination Survey III data from the National Center for Health Statistics, RA and diabetes were identified using several classification schemes. In total, 5302 survey participants aged >or= 60 years were included in logistic regression analyses taking survey weights into account. We also conducted sensitivity analyses restricting the study population to participants not recently prescribed glucocorticoids and fasting at least 8 hours prior to blood draw, as well as data incorporated from the Multiple Imputation Project. RESULTS: Among the 5302 participants aged >or= 60, 144 participants had RA and 24 of these also were found to have prevalent diabetes. The adjusted odds ratios for the cross-sectional association between RA and diabetes ranged from 1.1 to 1.5, but did not reach statistical significance. CONCLUSION: While this study cannot definitively rule out a modest non-null association, we can conclude that there is no evidence of a strong cross-sectional association between prevalent RA and diabetes in subjects aged >or= 60 years. Future longitudinal studies with more participants with RA are required to further evaluate a possible association between RA and the incidence of diabetes.

Aged↗

PubMed2006

Fatigue increases the risk of injury from sharp devices in medical trainees: results from a case-crossover study.

BACKGROUND: Extreme fatigue in medical trainees likely compromises patient safety, but regulations that limit trainee work hours have been controversial. It is not known whether extreme fatigue compromises trainee safety in the healthcare workplace, but evidence of such a relationship would inform the current debate on trainee work practices. Our objective was to evaluate the relationship between fatigue and workplace injury risk among medical trainees and nontrainee healthcare workers. DESIGN: Case-crossover study. SETTING: Five academic medical centers in the United States and Canada. PARTICIPANTS: Healthcare workers reporting to employee healthcare clinics for evaluation of needlestick injuries and other injuries related to sharp instruments and devices (sharps injuries). Consenting workers completed a structured interview about work patterns, time at risk of injury, and frequency of fatigue. RESULTS: Of 350 interviewed subjects, 109 (31%) were medical trainees. Trainees worked more hours per week (P<.001) and slept less the night before an injury (P<.001) than did other healthcare workers. Fatigue increased injury risk in the study population as a whole (incidence rate ratio [IRR], 1.40 [95% confidence interval {CI}, 1.03-1.90]), but this effect was limited to medical trainees (IRR, 2.94 [95% CI, 1.71-5.07]) and was absent for other healthcare workers (IRR, 0.97 [95% CI, 0.66-1.42]) (P=.001).Conclusions. Long work hours and sleep deprivation among medical trainees result in fatigue, which is associated with a 3-fold increase in the risk of sharps injury. Efforts to reduce trainee work hours may result in reduced risk of sharps-related injuries among this group.

Academic Medical Centers↗

PubMed2006

Holiday review. Early to bed and early to rise: does it matter?

BACKGROUND: Controversy remains about whether early to bed and early to rise makes a man healthy, wealthy and wise (the Ben Franklin hypothesis), or healthy, wealthy and dead (the James Thurber hypothesis). METHODS: As part of the Determinants of Myocardial Infarction Onset Study, we determined through personal interviews the bedtimes and wake times of 949 men admitted to hospital with acute myocardial infarction. Participants reported their educational attainment and zip code of residence, from which local median income was estimated. We followed participants for mortality for a mean of 3.7 years. We defined early-to-bed and early-to-rise respectively as a bedtime before 11 pm and wake time before 6:30 am. RESULTS: Hours in bed were inversely associated with number of cups of coffee consumed (age-adjusted Spearman correlation coefficient r -0.07, p = 0.03). The mortality of early-to-bed, early-to-risers did not differ significantly from other groups. There was also no relation between bed habits and local income, nor with educational attainment. INTERPRETATION: Our results refute both the Franklin and Thurber hypotheses. Early to bed and early to rise is not associated with health, wealth or wisdom.

Aged↗

PubMed2006

Renal dysfunction increases the risk of saphenous vein graft occlusion: results from the Post-CABG trial.

OBJECTIVES: Saphenous vein grafts are common among patients with a history of coronary artery bypass graft (CABG) surgery. Chronic kidney disease (CKD) is an established cardiovascular risk factor, but its role in graft disease has not been evaluated. METHODS AND RESULTS: The Post-CABG Trial randomized 1351 patients who had undergone CABG surgery 1-11 years earlier to high- or low-dose lovastatin and to low-dose warfarin or placebo. Coronary angiography was conducted at baseline and after a median follow-up time of 4.2 years. Subjects were grouped according to their baseline estimated glomerular filtration rate (eGFR). The primary trial endpoint was significant graft disease progression assessed angiographically. Additional pre-defined endpoints included occlusion of grafts patent at baseline, change in minimum lumen diameter, and a composite endpoint of recurrent clinical events. Decreasing eGFR was associated with an increased risk of graft occlusion (P(trend)=0.040), but not substantial atherosclerotic progression (P(trend)=0.30), per-graft change in minimum lumen diameter (P(trend)=0.067), or recurrent clinical events (P(trend)=0.86). We did not observe significant effect modification of treatment effects by the presence of CKD. CONCLUSIONS: CKD may be associated with increased risk of atherosclerotic plaque disruption rather than atherosclerotic progression in saphenous vein grafts.

Aged↗

PubMed2006

A 39-year-old woman with hypercholesterolemia.

Ms T, a 39-year-old woman, has a total cholesterol level of 277 mg/dL (7.17 mmol/L) and well-controlled hypertension; her brother had a stroke in his 30s. She is primarily concerned with her mother's history of breast cancer, but she would like to know if she can take a dietary supplement or if she needs to take cholesterol-lowering medication, and if so, whether she will need to continue it as well as adhere to her diet for the rest of her life. Her estimated 10-year risk of developing coronary heart disease (CHD) is 1% to 2% using the Framingham Risk Score, but that may underestimate her true risk as an African American woman with a family history of CHD. Recommendations for her, her longer-term risk for CHD, and evidence for lipid-lowering therapies are discussed.

Adult↗

PubMed2006

The association of alcohol consumption and incident heart failure: the Cardiovascular Health Study.

OBJECTIVES: We investigated the association between alcohol consumption and incident congestive heart failure (CHF) both overall and after adjusting for incident myocardial infarction (MI). BACKGROUND: Moderate alcohol consumption has been associated with lower risk of CHF and MI. METHODS: The Cardiovascular Health study, a prospective cohort study of cardiovascular disease risk factors and outcomes, followed 5,888 subjects > or =65 years old for 7 to 10 years. Cox models were used to estimate the adjusted risk of CHF by reported alcohol consumption. RESULTS: There were 5,595 subjects at baseline at risk for incident CHF with alcohol data and 1,056 events during follow-up. Compared with abstainers, the adjusted risk of CHF was lower among subjects who reported consuming 1 to 6 drinks per week (hazard ratio [HR] 0.82, 95% confidence interval [CI] 0.67 to 1.00, p = 0.05) and 7 to 13 drinks per week (HR 0.66, 95% CI 0.47 to 0.91, p = 0.01). Time-dependent adjustment for incident MI altered only slightly the association between moderate alcohol consumption and CHF (for 1 to 6 drinks per week, HR 0.84, 95% CI 0.65 to 1.04; for 7 to 13 drinks per week, HR 0.69, 95% CI 0.49 to 0.99). Baseline former drinkers had a higher risk of CHF than abstainers (HR 1.51, p < 0.01), but those who quit during the study did not have a higher risk (HR 0.83, 95% CI 0.66 to 1.03). CONCLUSIONS: Moderate alcohol use is associated with a lower risk of incident CHF among older adults, even after accounting for incident MI and other factors.

Aged↗

PubMed2006

Cardiovascular safety update of Tadalafil: retrospective analysis of data from placebo-controlled and open-label clinical trials of Tadalafil with as needed, three times-per-week or once-a-day dosing.

Because most men with erectile dysfunction have underlying vascular disease, it is important to update the cardiovascular safety profile of medications used in the treatment of erectile dysfunction. This retrospective analysis evaluated serious cardiovascular treatment-emergent adverse events (CVTEAEs) reported in 36 clinical trials of tadalafil, a phosphodiesterase-5 inhibitor used for the treatment of erectile dysfunction. A serious CVTEAE was defined as myocardial infarction, cardiovascular death, or cerebrovascular death. In the 36 trials, 12,487 men (mean age 55 years) with erectile dysfunction received tadalafil, with 5,771 patient-years (PYs) of exposure, and 2,047 men (mean age 56 years) received placebo, with 460 PYs of exposure. Tadalafil 2 to 50 mg was taken as needed, 3 times/week, or once a day. Co-morbidities at baseline included hypertension (31%), diabetes (21%), hyperlipidemia (17%), and coronary artery disease (5%). Across all trials, the incidence rate of serious CVTEAEs was 0.40/100 PYs in tadalafil-treated patients and 0.43/100 PYs in placebo-treated patients. In patients taking tadalafil as needed, 3 times/week, or once a day, the incidence rates of serious CVTEAEs ranged from 0.17 to 0.54/100 PYs across placebo-controlled and open-label trials. In conclusion, the incidence rates of serious CVTEAEs were comparable among men with erectile dysfunction taking tadalafil as needed, 3 times/week, or once a day, and these rates were also comparable with those in placebo-treated patients. In this clinical trial population of men with erectile dysfunction, tadalafil was not associated with an increased risk for serious cardiovascular adverse events.

Aged↗

PubMed2006

Particulate air pollution and hospital admissions for congestive heart failure in seven United States cities.

The association between short-term elevations in ambient particulate air pollution and increased cardiovascular morbidity and mortality is well documented. Ambient particles may also trigger acute decompensation in patients with congestive heart failure (CHF), but this hypothesis has not been evaluated in a systematic manner. This study evaluated the association between daily levels of respirable particulate matter of aerodynamic diameters < or =10 microm (PM10) and the rate of hospitalization from the emergency room for CHF in Medicare recipients (age > or = 65 years) in 7 United States cities from 1986 and 1999. The time-stratified case-crossover design was used to separately estimate the effect of a 10 microg/m3 increase in PM10 in each city. A combined random-effects estimate was then obtained from the city-specific effect estimates. There were 292,918 admissions with primary diagnoses of CHF during the observation period. Overall, a 10 microg/m3 increase in PM10 was associated with a 0.72% (95% confidence interval 0.35% to 1.10%) increase in the rate of admission for CHF on the same day. The effect of PM10 appeared to be less in patients with secondary diagnoses of hypertension. There was no consistent effect modification by age, gender, race, or any other secondary diagnosis evaluated. In conclusion, these results support the hypothesis that elevated levels of particulate air pollution, below the current limits set by the United States Environmental Protection Agency, are associated with an increase in the rate of hospital admission for exacerbation of CHF.

Aged↗

PubMed2006

Age-specific fluoride exposure in drinking water and osteosarcoma (United States).

OBJECTIVE: We explored age-specific and gender-specific effects of fluoride level in drinking water and the incidence of osteosarcoma. METHODS: We used data from a matched case-control study conducted through 11 hospitals in the United States that included a complete residential history for each patient and type of drinking water (public, private well, bottled) used at each address. Our analysis was limited to cases less than 20 years old. We standardized fluoride exposure estimates based on CDC-recommended target levels that take climate into account. We categorized exposure into three groups (<30%, 30-99%, >99% of target) and used conditional logistic regression to estimate odds ratios. RESULTS: Analysis is based on 103 cases under the age of 20 and 215 matched controls. For males, the unadjusted odds ratios for higher exposures were greater than 1.0 at each exposure age, reaching a peak of 4.07 (95% CI 1.43, 11.56) at age 7 years for the highest exposure. Adjusting for potential confounders produced similar results with an adjusted odds ratio for males of 5.46 (95% CI 1.50, 19.90) at age 7 years. This association was not apparent among females. CONCLUSIONS: Our exploratory analysis found an association between fluoride exposure in drinking water during childhood and the incidence of osteosarcoma among males but not consistently among females. Further research is required to confirm or refute this observation.

Adolescent↗

PubMed2006

Alcohol consumption, atherosclerotic progression, and prognosis among patients with coronary artery bypass grafts.

BACKGROUND: Although moderate drinking has been associated with lower mortality among patients after myocardial infarction, its relationship with prognosis and graft obstruction among patients with coronary artery bypass grafts is unknown. METHODS: We studied 1351 patients enrolled in the Post-CABG trial, who had undergone coronary bypass surgery 1 to 11 years before entry. Participants were randomly assigned to lovastatin in low or high doses and to low-dose warfarin or placebo in a factorial design. Participants underwent coronary angiography at baseline and after a mean follow-up of 4.3 years and were followed up for a composite end point of death, myocardial infarction, stroke, bypass surgery, or angioplasty. We categorized reported weekly alcohol intake as abstention (<1 drink), light (1-6 drinks), moderate (7-13 drinks), and heavier (> or =14 drinks). RESULTS: During follow-up, 238 participants sustained a clinical event. Moderate drinking was associated with a trend toward both fewer clinical events (hazard ratio 0.7, 95% CI 0.4-1.1) and less angiographic progression (odds ratio 0.7, 95% CI 0.5-1.1), although neither of these effects were statistically significant. High-density lipoprotein cholesterol appeared to account for one third of the trend toward lower risk among moderate drinkers. CONCLUSION: We did not demonstrate statistically significant differences in prognosis according to alcohol intake in this study, although there were inverse trends between moderate drinking and both morbidity and graft progression of a magnitude similar to studies in other populations. Larger studies of alcohol intake among patients with coronary artery bypass grafts are needed.

Alcohol Drinking↗

PubMed2006

A prospective study of risk factors for erectile dysfunction.

PURPOSE: We examined the impact of obesity, physical activity, alcohol use and smoking on the development of erectile dysfunction. MATERIALS AND METHODS: Subjects included 22,086 United States men 40 to 75 years old in the Health Professionals Followup Study cohort who were asked to rate their erectile function for multiple periods on a questionnaire mailed in 2000. Men who reported good or very good erectile function and no major chronic disease before 1986 were included in the analyses. RESULTS: Of men who were healthy and had good or very good erectile function before 1986, 17.7% reported incident erectile dysfunction during the 14-year followup. Obesity (multivariate relative risk 1.9, 95% CI 1.6-2.2 compared to men of ideal weight in 1986) and smoking (RR 1.5, 95% CI 1.3-1.7) in 1986 were associated with an increased risk of erectile dysfunction, while physical activity (RR 0.7, 95% CI 0.7-0.8 comparing highest to lowest quintile of physical activity) was associated with a decreased risk of erectile dysfunction. For men in whom prostate cancer developed during followup, smoking (RR 1.4, 95% CI 1.0-1.9) was the only lifestyle factor associated with erectile dysfunction. CONCLUSIONS: Reducing the risk of erectile dysfunction may be a useful and to this point unexploited motivation for men to engage in health promoting behaviors. We found that obesity and smoking were positively associated, and physical activity was inversely associated with the risk of erectile dysfunction developing.

Adult↗

PubMed2006

Tea consumption and infarct-related ventricular arrhythmias: the determinants of myocardial infarction onset study.

BACKGROUND: Tea consumption is associated with lower post-infarct mortality among patients with acute myocardial infarction. We previously found preliminary evidence that tea consumption may also be associated with lower risk of infarct-related ventricular arrhythmias. METHODS: Between 1989 and 1996, 3882 subjects with AMI were enrolled in the two phases of the Determinants of Myocardial Infarction Onset Study a median of four days after admission. Trained interviewers assessed self-reported usual tea and coffee consumption during the year prior to infarction with a standardized questionnaire. We examined the prevalence of ventricular arrhythmias in the two phases of the study separately and together. RESULTS: Among the 1912 patients with complete information in the first phase, the prevalence of ventricular arrhythmias was 16% among abstainers from tea, 11% among moderate tea drinkers (<14 cups per week), and 14% among heavier tea drinkers (> or =14 cups per week) (p homogeneity = 0.03). Among the 1791 patients with comparable information in the second phase, the corresponding prevalence rates were 11%, 8%, and 8%, respectively (p = 0.06). When the phases were combined, the adjusted odds ratios for VA were 0.7 (95% confidence interval, 0.6-0.9) among moderate tea drinkers and 0.9 (95% confidence interval, 0.7-1.2) among heavier tea drinkers. The findings were of similar direction for both ventricular tachycardia and fibrillation. In contrast, there was higher risk of VA with increasing coffee intake (odds ratio for >14 cups per week 1.3; 95% confidence interval, 1.0-1.7; p trend 0.02). CONCLUSIONS: Moderate tea intake is associated with a lower prevalence, and higher coffee intake with a slightly higher prevalence, of ventricular arrhythmias among patients hospitalized with acute myocardial infarction. If the association with tea intake is confirmed, it may suggest new approaches to prevention of ischemia-related arrhythmias.

Analysis of Variance↗

PubMed2006

Alcohol consumption and risk of coronary heart disease in older adults: the Cardiovascular Health Study.

OBJECTIVES: To evaluate several aspects of the relationship between alcohol use and coronary heart disease in older adults, including beverage type, mediating factors, and type of outcome. DESIGN: Prospective cohort study. SETTING: Four U.S. communities. PARTICIPANTS: Four thousand four hundred ten adults aged 65 and older free of cardiovascular disease at baseline. MEASUREMENTS: Risk of incident myocardial infarction or coronary death according to self-reported consumption of beer, wine, and spirits ascertained yearly. RESULTS: During an average follow-up period of 9.2 years, 675 cases of incident myocardial infarction or coronary death occurred. Compared with long-term abstainers, multivariate relative risks of 0.90 (95% confidence interval (CI)=0.71-1.14), 0.93 (95% CI=0.73-1.20), 0.76 (95% CI=0.53-1.10), and 0.58 (95% CI=0.39-0.86) were found in consumers of less than one, one to six, seven to 13, and 14 or more drinks per week, respectively (P for trend=.007). Associations were similar for secondary coronary outcomes, including nonfatal and fatal events. No strong mediators of the association were identified, although fibrinogen appeared to account for 9% to 10% of the relationship. The associations were statistically similar for intake of wine, beer, and liquor and generally similar in subgroups, including those with and without an apolipoprotein E4 allele. CONCLUSION: In this population, consumption of 14 or more drinks per week was associated with the lowest risk of coronary heart disease, although clinicians should not recommend moderate drinking to prevent coronary heart disease based on this evidence alone, because current National Institute on Alcohol Abuse and Alcoholism guidelines suggest that older adults limit alcohol intake to one drink per day.

Aged↗

PubMed2006

Depressive symptoms, social isolation, and progression of coronary artery atherosclerosis: the Stockholm Female Coronary Angiography Study.

BACKGROUND: Although both depressive symptoms and social isolation in relation to coronary heart disease have been studied previously, few have examined their joint effects on coronary atherosclerosis progression in women. METHOD: Among the women enrolled in the Stockholm Female Coronary Angiography Study, Sweden, between 1991 and 1994, 102 were evaluated for coronary atherosclerosis progression using a computer-assisted standardized assessment, repeated quantitative coronary angiographic documentation, of the mean luminal diameter change over 3 years in 10 predefined coronary segments. Depressive symptoms and social isolation were assessed by standard questionnaires. RESULTS: Multivariable controlled mixed model ANOVAs revealed that women who were both depressed and socially isolated had the greatest disease progression: their absolute mean luminal diameter decreased by 0.18 mm [95% confidence interval (CI) = 0.11-0.24] and their percent narrowing was 5.5% (95% CI = 3.6-7.4), whereas in women who lacked both psychological risk factors, the mean luminal diameter decrease was 0.04 mm and their percent narrowing was 0.9%. These associations were independent of the baseline luminal diameter and standard risk factors, including age, smoking history, hypertension, and high-density lipoproteins. CONCLUSIONS: In women with coronary disease, depressive symptoms and social isolation in combination accelerated disease progression, suggesting a direct psychosocial effect on the atherosclerotic process. These findings provide an additional opportunity for therapeutic and preventive efforts against progression of coronary disease in women.

Adult↗

PubMed2006

Increased risk of paroxysmal atrial fibrillation episodes associated with acute increases in ambient air pollution.

OBJECTIVES: We reported previously that 24-hr moving average ambient air pollution concentrations were positively associated with ventricular arrhythmias detected by implantable cardioverter defibrillators (ICDs). ICDs also detect paroxysmal atrial fibrillation episodes (PAF) that result in rapid ventricular rates. In this same cohort of ICD patients, we assessed the association between ambient air pollution and episodes of PAF. DESIGN: We performed a case-crossover study. PARTICIPANTS: Patients who lived in the Boston, Massachusetts, metropolitan area and who had ICDs implanted between June 1995 and December 1999 (n=203) were followed until July 2002. EVALUATIONS/MEASUREMENTS: We used conditional logistic regression to explore the association between community air pollution and 91 electrophysiologist-confirmed episodes of PAF among 29 subjects. RESULTS: We found a statistically significant positive association between episodes of PAF and increased ozone concentration (22 ppb) in the hour before the arrhythmia (odds ratio=2.08; 95% confidence interval=1.22, 3.54; p=0.001). The risk estimate for a longer (24-hr) moving average was smaller, thus suggesting an immediate effect. Positive but not statistically significant risks were associated with fine particles, nitrogen dioxide, and black carbon. CONCLUSIONS: Increased ambient O3 pollution was associated with increased risk of episodes of rapid ventricular response due to PAF, thereby suggesting that community air pollution may be a precipitant of these events.

Aged↗

PubMed2005

Binge drinking and mortality after acute myocardial infarction.

BACKGROUND: Moderate drinkers have a lower risk of mortality after myocardial infarction (MI). Although binge drinking has been associated with a higher risk of MI in some studies, its relation to prognosis after MI is uncertain. METHODS AND RESULTS: In a prospective, inception cohort study conducted at 45 US hospitals, 1935 patients hospitalized with a confirmed MI between 1989 and 1994 underwent detailed personal interviews. Patients reported their usual frequency of binge drinking of beer, wine, and liquor, defined as intake of 3 or more drinks within 1 to 2 hours, and were followed up for mortality for a median of 3.8 years. Of 1919 eligible patients, 250 (94% men) reported binge drinking during the prior year, and a total of 318 patients died during follow-up. Binge drinkers had a 2-fold higher risk of mortality than drinkers who did not binge (hazard ratio, 2.0; 95% confidence interval, 1.3 to 3.0). A comparison of 192 binge drinkers and 192 other patients matched on propensity scores yielded a similar result. The association between binge drinking and total mortality tended to be similar among patients whose usual alcohol intake was light or heavier and for binge drinkers who consumed beer, wine, or liquor. Usual alcohol intake was inversely associated with mortality, but binge drinking completely attenuated this relation. CONCLUSIONS: Our results suggest that alcohol consumption may be linked to potential hazards among patients who survive acute MI. Although moderate intake has been associated with lower mortality, binge drinking, even among light drinkers, appears to be associated with 2-fold higher mortality.

Adult↗

PubMed2005

Systematic review of the effects of ginseng on cardiovascular risk factors.

OBJECTIVE: To examine the evidence for the efficacy of ginseng (Panax spp.) on cardiovascular risk factors, including blood pressure, lipid profiles, and blood glucose, and to summarize reported cardiovascular adverse events. DATA SOURCES: We searched MEDLINE, AMED, BIOSIS, CAB, EMBASE, and the Cochrane Controlled Trials databases through July 2005 and performed hand searches of bibliographies. STUDY SELECTION AND DATA EXTRACTION: Short- or long-term, randomized, controlled trials and nonrandomized studies published in English were included. Data were extracted in a standardized manner, and 2 independent investigators assessed methodologic quality of the studies. Thirty-four studies were identified with results for blood pressure, lipids, and/or blood glucose. Due to heterogeneity of the studies, we were unable to perform a meta-analysis. Data on cardiovascular adverse events were extracted from events reported in identified studies and from case reports. DATA SYNTHESIS: The majority of studies were short term. Ginseng may slightly decrease blood pressure compared with placebo (range 0-4%). We found mixed results for an effect on lipids, with 5 of 9 studies showing improvement in one or more lipid parameters compared with baseline (range 7-44%). We identified several studies showing that ginseng lowers blood glucose, but overall studies were inconsistent. CONCLUSIONS: Current evidence does not support the use of ginseng to treat cardiovascular risk factors. Some studies suggest a small reduction in blood pressure. Despite some evidence showing that ginseng lowers blood glucose and improves lipid profiles, well-designed, randomized, controlled trials evaluating its effects are lacking.

Blood Glucose↗

PubMed2005

It's not the heat, it's the humidity: wet weather increases legionellosis risk in the greater Philadelphia metropolitan area.

BACKGROUND: Legionella species are abundant in the environment and are increasingly recognized as a cause of severe pneumonia. Increases in cases of community-acquired legionellosis in the greater Philadelphia metropolitan area (GPMA) led to concern that changing environmental factors could influence occurrence of disease. METHODS: We evaluated the association between weather patterns and occurrence of legionellosis in the GPMA, using both traditional Poisson regression analysis and a case-crossover study approach. The latter approach controls for seasonal factors that could confound the relationship between weather and occurrence of disease and permits the identification of acute weather patterns associated with disease. RESULTS: A total of 240 cases of legionellosis were reported between 1995 and 2003. Cases occurred with striking summertime seasonality. Occurrence of cases was associated with monthly average temperature (incidence rate ratio [IRR] per degree Celsius, 1.07 [95% confidence interval [CI], 1.05-1.09]) and relative humidity (IRR per 1% increase in relative humidity, 1.09 [95% CI, 1.06-1.12]) by Poisson regression analysis. However, case-crossover analysis identified an acute association with precipitation (odds ratio [OR], 2.48 [95% CI, 1.30-3.12]) and increased humidity (OR per 1% increase in relative humidity, 1.08 [95% CI, 1.05-1.11]) 6-10 days before occurrence of cases. A significant dose-response relationship for occurrence of cases was seen with both precipitation and increased humidity. CONCLUSIONS: Although, in the GPMA, legionellosis occurred predominantly during summertime, the acute occurrence of disease is best predicted by wet, humid weather. This finding is consistent with the current understanding of the ecological profile of this pathogen and supports the contention that sporadic legionellosis occurs through contamination of water sources.

Adolescent↗