绝经后女性心血管危险因素与骨密度的相关关系

目的:本研究的目的是评估绝经后女性冠心病患者心血管危险因素与骨密度的相关关系。方法:评估216例拟行冠脉造影的绝经后女性冠心病患者的危险因素,并于冠脉造影检查前日或次日行骨密度检测,依据T值将受试者分为2组:骨量正常组(T值大于-1SD)、低骨量组(T值小于-1SD)。结果:2组患者在BMI、糖尿病、高血压及吸烟等均无显著性差异。低骨量组冠心病的发生率及年龄显著高于骨量正常组。Logistic回归分析显示绝经后女性冠心病患者年龄与骨密度独立相关(OR=1.072 CI:1.036～1.11p=0.001)。结论:年龄与绝经后女性冠心病患者骨密度负相关,心血管病危险因素或冠心病与骨量不相关。     

The Role of Apolipoprotein E as a Risk Factor for an Earlier Age at Onset for Machado-Joseph Disease Is Doubtful

Machado-Joseph disease (MJD) is an inherited neurodegenerative disease caused by an expanded CAG repeat in the ATXN3 gene. Although the principal genetic determinant of the age at onset (AAO) is the length of the expanded CAG repeat, the additional genetic contribution of MJD toward the AAO has mostly not yet been clarified. It was recently suggested in two independent studies that apolipoprotein E (APOE) might be associated with AAO variability in MJD patients. To identify the potential modifier effect of APOE polymorphisms on the AAO of MJD patients, 403 patients with MJD (confirmed by molecular tests) from eastern and southeastern China were enrolled in the present study. CAG repeats in the ATXN3 and APOE polymorphisms were genotyped. Data were analyzed using a statistical package. No contribution of APOE polymorphisms to the variance in disease onset was observed using ANCOVA (F = 0.183, P = 0.947). However, significant effects on the AAO of MJD were found for the normal ATXN3 allele and for the interaction of mutant and normal ATXN3 alleles in a multiple linear regression model (P = 0.043 and P = 0.035, respectively). Our study does not support a role for APOE as a genetic modifier of the AAO of MJD. Additionally, our study presents evidence that the normal ATXN3 allele and its interaction with mutant alleles contribute toward AAO variance in MJD patients.     

The PlA1/A2 Polymorphism of Glycoprotein IIIa as a Risk Factor for Stroke: A Systematic Review and Meta-Analysis

Background

The PlA1/A2 polymorphism of glycoprotein IIIa (GPIIIa) has been reported to be associated with risk of stroke in some studies, although other studies suggest no such association. This meta-analysis and systematic review was conducted to investigate the hypothesis that carriage of the PlA2 allele is a risk factor for stroke.

Methods

Electronic databases (MEDLINE and EMBASE) were searched for all articles evaluating carriage of the PlA2 allele and the incidence of stroke. Pooled odds ratios (ORs) were calculated using fixed-effect and random-effect models.

Findings

A total of 35 articles were eligible for inclusion, of which 25 studies were suitable for statistical analysis. For carriage of the PlA2 allele, OR 1.12 (n = 11,873; 95% CI = 1.03–1.22; p = 0.011) was observed for the incidence of stroke in adults, with subgroup analyses identifying the association driven by stroke of an ischaemic (n = 10,494; OR = 1.15, 95% CI = 1.05–1.27; p = 0.003) but not haemorrhagic aetiology (n = 2,470; OR = 0.90, 95% CI = 0.71–1.14; p = 0.398). This association with ischaemic stroke was strongest in individuals homozygous for the PlA2 allele compared to those homozygous for wild-type PlA1 (n = 5,906; OR = 1.74, 95% CI = 1.34–2.26; p<0.001). Subgroup analysis of ischaemic stroke subtypes revealed an increased association with stroke of cardioembolic (n = 1,271; OR 1.56, 95% CI 1.14–2.12; p = 0.005) and large vessel (n = 1,394; OR = 1.76, 95% CI 1.34–2.31; p<0.001) aetiology, but not those of small vessel origin (n = 1,356; OR = 0.99, 95% CI 0.74–1.33; p = 0.950). Egger''s regression test suggested a low probability of publication bias for all analyses (p>0.05).

Conclusions

The totality of published data supports the hypothesis that carriage of the PlA2 polymorphism of GPIIIa is a risk factor for ischaemic strokes, and specifically those of cardioembolic and large vessel origin.     

Inadequate Exercise as a Risk Factor for Sepsis Mortality

Objective

Test whether inadequate exercise is related to sepsis mortality.

Research Design and Methods

Mortality surveillance of an epidemiological cohort of 155,484 National Walkers'' and Runners'' Health Study participants residing in the United States. Deaths were monitored for an average of 11.6-years using the National Death index through December 31, 2008. Cox proportional hazard analyses were used to compare sepsis mortality (ICD-10 A40-41) to inadequate exercise (<1.07 METh/d run or walked) as measured on their baseline questionnaires. Deaths occurring within one year of the baseline survey were excluded.

Results

Sepsis was the underlying cause in 54 deaths (sepsis_underlying) and a contributing cause in 184 deaths (sepsis_contributing), or 238 total sepsis-related deaths (sepsis_total). Inadequate exercise was associated with 2.24-fold increased risk for sepsis_underlying (95%CI: 1.21 to 4.07-fold, P = 0.01), 2.11-fold increased risk for sepsis_contributing (95%CI: 1.51- to 2.92-fold, P<10⁻⁴), and 2.13-fold increased risk for sepsis_total (95%CI: 1.59- to 2.84-fold, P<10⁻⁶) when adjusted for age, sex, race, and cohort. The risk increase did not differ significantly between runners and walkers, by sex, or by age. Sepsis_total risk was greater in diabetics (P = 10⁻⁵), cancer survivors (P = 0.0001), and heart attack survivors (P = 0.003) and increased with waist circumference (P = 0.0004). The sepsis_total risk associated with inadequate exercise persisted when further adjusted for diabetes, prior cancer, prior heart attack and waist circumference, and when excluding deaths with cancer, or cardiovascular, respiratory, or genitourinary disease as the underlying cause. Inadequate exercise also increased sepsis_total risk in 2163 baseline diabetics (4.78-fold, 95%CI: 2.1- to 13.8-fold, P = 0.0001) when adjusted, which was significantly greater (P = 0.03) than the adjusted risk increase in non-diabetics (1.80-fold, 95%CI: 1.30- to 2.46-fold, P = 0.0006).

Conclusion

Inadequate exercise is a risk factor for sepsis mortality, particular in diabetics.     

Overweight as a Prognostic Factor for Triple-Negative Breast Cancers in Chinese Women

Purpose

Obesity is associated with poorer outcomes in patients with hormone receptor-positive breast cancers, but this association is not well established for women with triple-negative breast cancers (TNBC). Here, we investigated the prognostic effects of body mass index (BMI) on clinical outcomes in patients with TNBC.

Methods

We identified 1106 patients with TNBC who met the inclusion criteria and were treated between January 2002 and June 2012. Clinical and biological features were collected to evaluate the relation between BMI and breast cancer-specific survival (BCSS) and overall survival (OS) after controlling for other clinically significant variables.

Results

Of 1106 patients, 656 (59.3%) were normal weight (BMI ≤24) and 450 patients (40.7%) were overweight(BMI>24). Median follow-up time was 44.8 months. Breast cancer specific death was observed in 140 patients. After adjusting for clinicopathologic risk factors, overweight was associated with OS (hazard ratio [HR]: 1.46, 95% confidence interval [CI]: 1.04-2.06, P =0.028) but not BCSS (HR: 1.34, 95% CI: 0.90–2.01, P =0.15)in all the patients with TNBC. When stratified with menopausal status, overweight was associated with BCSS and OS (HR: 2.27, 95% CI: 1.11-4.63, P = 0.024 and HR: 2.16, 95% CI: 1.21-3.87, P = 0.010, respectively) in premenopausal women. BMI was not associated with BCSS or OS in postmenopausal women.

Conclusions

Overweight is an independent prognostic factor of OS in all women with TNBC, and menopause status may be a mitigating factor. Among premenopausal women, overweight women are at a greater risk of poor prognosis than normal weight women. If validated, these findings should be considered in developing preventive programs.     

The Role of Thiamine as a Factor for the Growth of Brochothrix thermosphacta

Thiamine enhances growth of the meat spoilage organism, Brochothrix thermosphacta. It fulfils some, but not all, of the yeast-extract requirement of this organism. Oxythiamine acts as a growth inhibitor at high concentrations and the inhibition is readily reversed by thiamine. The possible roles of thiamine in the metabolism of Br. thermosphacta are discussed.     

Visceral Fat Accumulation as a Risk Factor for Prostate Cancer

Objective: No clear association between obesity or body fat distribution and prostate cancer has been shown. We investigated the relation between visceral fat accumulation as measured by computed tomography (CT) and the occurrence of prostate cancer. Research Methods and Procedures: We compared body fat distribution assessed by a direct method (CT) in 63 prostate cancer cases with 63 age‐matched healthy community controls. A CT scan at the level of the fourth lumbar vertebra was performed in all participants. Results: Patients presented a significantly higher mean total abdominal fat area (509.2 ± 226.1 vs. 334.3 ± 132.9 cm², p < 0.001), mostly because of a higher mean visceral fat area (VF; 324.7 ± 145.6 vs. 177.4 ± 88.4 cm², p < 0.001) and a significantly higher mean ratio between visceral and subcutaneous fat areas (V/S ratio; 1.8 ± 0.4 vs. 1.2 ± 0.4, p < 0.001). A significantly higher risk of prostate cancer was found for participants with higher VF (odds ratio = 4.6; 95% confidence interval = 2.6 to 8.2 per SD increase) and V/S ratio (odds ratio = 6.0; 95% confidence interval = 2.3 to 11.0 per SD increase). Discussion: These results suggest a role for visceral obesity, quantified by CT, as a risk factor for prostate cancer. The action of the adipocytokines secreted by visceral fat cells, steroid hormone disturbances, and increased levels of insulin or other hormones noted in visceral obesity may explain this association.     

The Association between Aortic Calcification and Fracture Risk in Postmenopausal Women in China: The Prospective Chongqing Osteoporosis Study

Purpose

Fractures are associated with cardiovascular diseases in the elderly. The purpose of the present study was to investigate the association between aortic calcification (AC) and the risk of vertebral fractures in postmenopausal Chinese women.

Methods

A prospective study with 5 years of follow-up in 1724 postmenopausal women (aged 50 years old and older) was conducted from July 2005 to June 2010. Dual energy X-ray absorptiometry was utilized to evaluate bone mineral density (BMD). Aortic calcification score (ACS) was determined by a semi-quantitative method and was further categorized into four groups. Cox proportional hazards models were established to assess the association between AC and the risk of vertebral fractures.

Results

For subjects with AC, the incidence of vertebral fractures was higher than that of those without AC (p<0.01). After adjustment for age and other potential confounders, it was found that severe AC (G4, ACS>6; G3, ACS = 3–6) was associated with vertebral fractures. Severe AC (G4) was associated with non-vertebral fractures. There were higher risk for the vertebral fractures in two groups and higher risk for non-vertebral fractures in one group.

Conclusions

The results of the current study indicate that severe AC is associated with a significantly increased risk of vertebral fractures and non-vertebral fractures in postmenopausal women in China.     

Characterization of Vascular Disease Risk in Postmenopausal Women and Its Association with Cognitive Performance

Objectives

While global measures of cardiovascular (CV) risk are used to guide prevention and treatment decisions, these estimates fail to account for the considerable interindividual variability in pre-clinical risk status. This study investigated heterogeneity in CV risk factor profiles and its association with demographic, genetic, and cognitive variables.

Methods

A latent profile analysis was applied to data from 727 recently postmenopausal women enrolled in the Kronos Early Estrogen Prevention Study (KEEPS). Women were cognitively healthy, within three years of their last menstrual period, and free of current or past CV disease. Education level, apolipoprotein E ε4 allele (APOE4), ethnicity, and age were modeled as predictors of latent class membership. The association between class membership, characterizing CV risk profiles, and performance on five cognitive factors was examined. A supervised random forest algorithm with a 10-fold cross-validation estimator was used to test accuracy of CV risk classification.

Results

The best-fitting model generated two distinct phenotypic classes of CV risk 62% of women were “low-risk” and 38% “high-risk”. Women classified as low-risk outperformed high-risk women on language and mental flexibility tasks (p = 0.008) and a global measure of cognition (p = 0.029). Women with a college degree or above were more likely to be in the low-risk class (OR = 1.595, p = 0.044). Older age and a Hispanic ethnicity increased the probability of being at high-risk (OR = 1.140, p = 0.002; OR = 2.622, p = 0.012; respectively). The prevalence rate of APOE-ε4 was higher in the high-risk class compared with rates in the low-risk class.

Conclusion

Among recently menopausal women, significant heterogeneity in CV risk is associated with education level, age, ethnicity, and genetic indicators. The model-based latent classes were also associated with cognitive function. These differences may point to phenotypes for CV disease risk. Evaluating the evolution of phenotypes could in turn clarify preclinical disease, and screening and preventive strategies.ClinicalTrials.gov {"type":"clinical-trial","attrs":{"text":"NCT00154180","term_id":"NCT00154180"}}NCT00154180     

The Aromatase Gene (CYP19A1) Variants and Circulating Hepatocyte Growth Factor in Postmenopausal Women

Background

Estrogen and androgen have been linked to the regulation of circulating hepatocyte growth factor (HGF), an adipose tissue-derived cytokine. It is possible that the CYP19A1 gene which alters sex hormones production may influence HGF levels. We examined the association between the CYP19A1 gene variants and plasma HGF concentrations.

Design

We evaluated 45 common and putative functional variants of CYP19A1 and circulating levels of HGF among 260 postmenopausal women who later developed colorectal cancer from the Women''s Health Initiative Observational Cohort. As the distribution of HGF levels was highly skewed, we transformed HGF concentrations for all women into a log-, ranked-, or normal score-scale value. Multiple linear regression with adjustment for age was used to evaluate the associations.

Results

We observed an association between the rs7172156, rs1008805, rs6493494, rs749292, and rs11636639 variants and HGF levels in ranked and normal score scales (corrected p values ≤0.02), although the association of these 5 SNPs with log-scale HGF was not significant (corrected p values ≥0.16). The associations remained unchanged after additional adjustment for hormone therapy use and estradiol levels. These 5 SNPs, which were in linkage disequilibrium (pairwise D′≥97%, r²≥56%), constituted a block with 2 common haplotypes accounting for 82% frequency. The most common haplotype, TCCCA, was associated with lower ranked- or normal score-transformed HGF levels (corrected p values ≤0.001), whereas the second most common haplotype, CTTCA, was associated with higher ranked- or normal score-transformed HGF levels (corrected p values ≤0.02).

Conclusion

Our findings of a potential association between the CYP19A1 variants and circulating HGF levels warrant confirmation in studies with larger sample size.     

Increased Visceral Adipose Tissue as a Potential Risk Factor in Patients with Embolic Stroke of Undetermined Source (ESUS)

Purpose

The etiology of an ischemic stroke remains undetermined in 20–35% of cases and many patients do not have any of the conventional risk factors. Increased visceral adipose tissue (VAT) is a suggested new risk factor for both carotid artery atherosclerosis (CAA) and atrial fibrillation (AF), but its role in the remaining stroke population is unknown. We assessed the amount of VAT in patients with embolic stroke of undetermined source (ESUS) after excluding major-risk cardioembolic sources, occlusive atherosclerosis, and lacunar stroke.

Methods

Altogether 58 patients (mean age 57.7±10.2 years, 44 men) with ischemic stroke of unknown etiology but without CAA, known AF or small vessel disease underwent computed tomography angiography and assessment of VAT. For comparison VAT values from three different reference populations were used. Conventional risk factors (smoking, hypertension, diabetes, increased total and LDL-cholesterol, decreased HDL-cholesterol) were also registered.

Results

Mean VAT area was significantly higher in stroke patients (205±103 cm² for men and 168±99 cm² for women) compared to all reference populations (P<0.01). 50% of male and 57% of female patients had an increased VAT area. In male patients, VAT was significantly higher despite similar body mass index (BMI). Increased VAT was more common than any of the conventional risk factors.

Conclusion

Increased VAT was found in over half of our patients with ESUS suggesting it may have a role in the pathogenesis of thromboembolism in this selected group of patients.     

Gestational Weight Gain as an Independent Risk Factor for Macrosomia in Women with Intermediate State Gestational Blood Glucose

Objective: Macrosomia is closely associated with gestational diabetes mellitus (GDM) but its relationship with maternal intermediate state gestational blood glucose (ISGBG; normal fasting blood glucose and 7.8 mmol/L <1 hour blood glucose &lsqb;BG] <10 mmol/L or 6.7 mmol/L <2 hour BG <8.5 mmol/L) is unclear. Here, we analyzed the clinical characteristics and pregnancy outcomes and explored risk factors for macrosomia in women with ISGBG.Methods: A total of 847 women with normal glucose tolerance gestation, 330 with ISGBG, and 99 with GDM were included. Maternal and fetal clinical data were collected and 3-point BG following oral glucose tolerance test, fasting insulin, glycated hemoglobin, and blood lipids profile were measured.Results: The incidence rate of macrosomia among the neonates of women with ISGBG was as high as 10.9%. In the ISGBG group, prepregnancy body mass index (BMI), gestational weight gain (GWG) and the proportion of women with excessive GWG (eGWG) were significantly higher in women with macrosomia compared with those who delivered a normal weight neonate. In women with ISGBG, neonate weight was positively correlated with maternal prepregnancy weight (r = 0.183, P<.01), prepregnancy BMI (r = 0.135, P<.01), and GWG (r = 0.255, P<.01), and negatively correlated with high-density lipoprotein cholesterol (r = -0.172, P<.01). Nonetheless, only eGWG was an independent risk factor (odds ratio = 3.18, 95% confidence interval = 1.26 to 7.88, P<.05) for macrosomia. The risk of macrosomia in pregnant women with prepregnancy BMI <25 kg/m² or BMI ≥25 kg/m² and eGWG was 3.39 and 3.27 times, respectively.Conclusion: The incidence rate of macrosomia is increased in women with ISGBG and eGWG is the strongest independent risk factor. In order to reduce the risk for macrosomia, timely lifestyle intervention to promote appropriate weight gain during pregnancy deserves evaluation.Abbreviations: AUC = area under the curve; BG = blood glucose; 1 hour BG = 1 hour blood glucose after OGTT; 2 hour BG = 2 hour blood glucose after OGTT; BMI = body mass index; CI = confidence interval; eGWG = excessive gestational weight gain; FBG = fasting blood glucose; FINS = fasting insulin; GDM = gestational diabetes mellitus; HbA1c = glycated hemoglobin; HDL-C = high-density lipoprotein cholesterol; HOMA-IR = homeostasis model assessment of insulin resistance index; ISGBG = intermediate state gestation blood glucose; LDL-C = low-density lipoprotein cholesterol; Ln = natural logarithm; MLBW = mature low birth weight; NGTG = normal glucose tolerance gestation; OGTT = oral glucose tolerance test; OR = odds ratio; SD = standard deviation     

Dopamine Transporter Genotype as a Risk Factor for Obesity in African-American Smokers

Objective: To assess the association between a polymorphism related to dopamine function, dopamine transport (SLC6A3), and obesity in smokers. Research Methods and Procedures: Logistic regression was used to assess the relationship between this genetic polymorphism and obesity (body mass index ≥ 30 kg/m²) from a sample of 510 smokers who smoked at least 10 cigarettes per day and who were participating in a study designed to examine genetic and nongenetic predictors of response to a pharmacological treatment. Results: The likelihood of obesity in African Americans (N = 90) with the 10/10 SLC6A3 genotype was 5.16 times that of African Americans with 9/9 or 9/10 SLC6A3 genotypes (odds ratio = 5.16, confidence interval = 1.60 to 16.65). There was no association of the SLC6A3 genotype with obesity for non-Hispanic whites (N = 420). Discussion: These results suggest that variants of the dopamine transporter gene may be related to obesity in African-American smokers. Possible mechanisms responsible for the association between dopamine transport and obesity in African-American smokers are discussed.     

Forced Sexual Experiences as Risk Factor for Self-Reported HIV Infection among Southern African Lesbian and Bisexual Women

Even though women who have sex with women are usually understood to be at no or very low risk for HIV infection, we explored whether lesbian and bisexual women in a geographical area with high HIV prevalence (Southern Africa) get tested for HIV and whether, among those women who get tested, there are women who live with HIV/AIDS. The study was conducted in collaboration with community-based organizations in Botswana, Namibia, South Africa and Zimbabwe. Data were collected via written surveys of women who in the preceding year had had sex with a woman (18 years and older; N = 591). Most participating women identified as lesbian and black. Almost half of the women (47.2%) reported ever having had consensual heterosexual sex. Engagement in transactional sex (lifetime) was reported by 18.6% of all women. Forced sex by men or women was reported by 31.1% of all women. A large proportion of the women reported to ever have been tested for HIV (78.3%); number of lifetime female and male partners was independently associated with having been tested; women who had engaged in transactional sex with women only or with women and men were less likely to have been tested. Self-reported HIV prevalence among tested women who knew their serostatus was 9.6%. Besides age, the sole independent predictor of a positive serostatus was having experienced forced sex by men, by women, or by both men and women. Study findings indicate that despite the image of invulnerability, HIV/AIDS is a reality for lesbian and bisexual women in Southern Africa. Surprisingly, it is not sex with men per se, but rather forced sex that is the important risk factor for self-reported HIV infection among the participating women. HIV/AIDS policy should also address the needs of lesbian, bisexual and other women who have sex with women.     

The Role of Cadmium as a Causative Agent of Recurrent Abortion in Egyptian Women

Environmental pollution is one of the ever surging problems receiving careful attention in Egypt, as well as in the world. It has been evidenced that environmental pollutants play an important role in the manifestations of severe reproductive-associated disorders. Among them, an environmental pollutant, Cd, has contributed to several deleterious effects. Maternal exposure to Cd is associated with low birthweight and an increase in spontaneous abortion. Spontaneous abortion is highly frustrating for both patients and physicians. The data from the present study reveal that there was a significant increase in blood level of Cd in the aborter groups as compared to the control group of healthy women. Also there was a significant decrease in serum ferritin, which correlated positively with abortion. Also, plasma levels of malondialdehyde were significantly elevated in aborter groups. There was also a highly significant increase in plasma 8-hydroxyl-2-deoxyguanosine in the aborter groups as compared to the control group, accompanied by a significant decrease in plasma carnosine in aborter groups as compared with the control group. In the same manner there was a reduction in the progesterone hormone in aborter groups. Our results suggest that exposure to Cd is associated with an increased risk of recurrent spontaneous abortion in Egyptian women.     

Hypercoagulability Is a Stronger Risk Factor for Ischaemic Stroke than for Myocardial Infarction: A Systematic Review

Background and Purpose

Hypercoagulability increases the risk of arterial thrombosis; however, this effect may differ between various manifestations of arterial disease.

Methods

In this study, we compared the effect of coagulation factors as measures of hypercoagulability on the risk of ischaemic stroke (IS) and myocardial infarction (MI) by performing a systematic review of the literature. The effect of a risk factor on IS (relative risk for IS, RR_IS) was compared with the effect on MI (RR_MI) by calculating their ratio (RRR = RR_IS/RR_MI). A relevant differential effect was considered when RRR was >1+ its own standard error (SE) or <1−SE.

Results

We identified 70 publications, describing results from 31 study populations, accounting for 351 markers of hypercoagulability. The majority (203/351, 58%) had an RRR greater than 1. A larger effect on IS risk than MI risk (RRE>1+1SE) was found in 49/343 (14%) markers. Of these, 18/49 (37%) had an RRR greater than 1+2SE. On the opposite side, a larger effect on MI risk (RRR<1-1SE) was found in only 17/343 (5%) markers.

Conclusions

These results suggest that hypercoagulability has a more pronounced effect on the risk of IS than that of MI.     

Environmental Contamination as a Risk Factor for Intra-Household Staphylococcus aureus Transmission

Background

The household is a recognized community reservoir for Staphylococcus aureus. This study investigated potential risk factors for intra-household S. aureus transmission, including the contribution of environmental contamination.

Methods

We investigated intra-household S. aureus transmission using a sample of multiple member households from a community-based case-control study examining risk factors for CA-MRSA infection conducted in Northern Manhattan. During a home visit, index subjects completed a questionnaire. All consenting household members were swabbed, as were standardized environmental household items. Swabs were cultured for S. aureus. Positive isolates underwent further molecular characterization. Intra-household transmission was defined as having identical strains among two or more household members. Multiple logistic regression was used to identify independent risk factors for transmission.

Results

We enrolled 291 households: 146 index cases, 145 index controls and 687 of their household contacts. The majority of indexes were Hispanic (85%), low income (74%), and female (67%), with a mean age of 31 (range 1–79). The average size of case and control households was 4 people. S. aureus colonized individuals in 62% of households and contaminated the environment in 54% of households. USA300 was the predominant clinical infection, colonizing and environmental strain. Eighty-one households had evidence of intra-household transmission: 55 (38%) case and 26 (18%) control households (P<.01). Environmental contamination with a colonizing or clinical infection strain (aOR: 5.4 [2.9–10.3] P<.01) and the presence of a child under 5 (aOR: 2.3 [1.2–4.5] P = .02) were independently associated with transmission. In separate multivariable models, environmental contamination was associated with transmission among case (aOR 3.3, p<.01) and control households (aOR 27.2, p<.01).

Conclusions

Environmental contamination with a colonizing or clinical infection strain was significantly and independently associated with transmission in a large community-based sample. Environmental contamination should be considered when treating S. aureus infections, particularly among households with multiple infected members.