Prevalence of MTHFR Polymorphisms in Patients With Hypermobile Ehlers-Danlos Syndrome and Hypermobile Spectrum Disorders in a US Hypermobility Clinic.

OBJECTIVE: Hypermobile Ehlers-Danlos syndrome (hEDS) and hypermobility spectrum disorders (HSD) are characterized by joint hypermobility, joint subluxations and dislocations, hyperextensible skin, and chronic and progressive multiorgan comorbidities. Diagnosing hEDS and HSD is difficult because of variable phenotypes and unknown genetic etiology. In our clinic, we observed many patients with hEDS and HSD with a high serum level of unmetabolized folate, which suggests that hypermobility may be linked to methylenetetrahydrofolate reductase (MTHFR)-mediated folate metabolism. The present study aims to examine the prevalence of MTHFR polymorphisms, C677T and A1298C, among patients with hEDS and HSD. METHODS: Clinical and demographic information of patients visiting our hypermobility clinic from January 2023 to July 2023 were retrospectively reviewed. Continuous variables were reported as mean ± SD and range, whereas categorical variables were reported as total count and percentage. RESULTS: Among 157 patients, 93% of patients were female patients, 52.2% were diagnosed with hEDS, and 47.8% were diagnosed with HSD. Interestingly, 85% of the patients had MTHFR C677T and/or A1298C polymorphisms in heterozygous or homozygous state. MTHFR 677CT/TT genotype was present in 52.9% of cases, and 49.7% of patients had 1298AC/CC genotype. In addition,14% of patients with hypermobility exhibited MTHFR 677TT genotype, 10.2% showed 1298CC genotype, and 17.2% displayed combined heterozygosity, collectively representing 41.4% hypermobile patients with two copies of MTHFR variant alleles. CONCLUSION: There is a high prevalence of MTHFR polymorphisms among patients with hypermobility, which supports the hypothesis that hypermobility may be dependent on folate status.

Personal PM(2.5) exposure among wildland firefighters working at prescribed forest burns in Southeastern United States.

This study investigated occupational exposure to wood and vegetative smoke in a group of 28 forest firefighters at prescribed forest burns in a southeastern U.S. forest during the winters of 2003-2005. During burn activities, 203 individual person-day PM(2.5) and 149 individual person-day CO samples were collected; during non-burn activities, 37 person-day PM(2.5) samples were collected as controls. Time-activity diaries and post-work shift questionnaires were administered to identify factors influencing smoke exposure and to determine how accurately the firefighters' qualitative assessment estimated their personal level of smoke exposure with discrete responses: "none" or "very little," "low," "moderate," "high," and "very high." An average of 6.7 firefighters were monitored per burn, with samples collected on 30 burn days and 7 non-burn days. Size of burn plots ranged from 1-2745 acres (avg = 687.8). Duration of work shift ranged from 6.8-19.4 hr (avg = 10.3 hr) on burn days. Concentration of PM(2.5) ranged from 5.9-2673 µg/m(3) on burn days. Geometric mean PM(2.5) exposure was 280 µg/m(3) (95% CL = 140, 557 µg/m(3), n = 177) for burn day samples, and 16 µg/m(3) (95% CL = 10, 26 µg/m(3), n = 35) on non-burn days. Average measured PM(2.5) differed across levels of the firefighters' categorical self-assessments of exposure (p < 0.0001): none to very little = 120 µg/m(3) (95% CL = 71, 203 µg/m(3)) and high to very high = 664 µg/m(3) (95% CL = 373, 1185 µg/m(3)); p < 0.0001 on burn days). Time-weighted average PM(2.5) and personal CO averaged over the run times of PM(2.5) pumps were correlated (correlation coefficient estimate, r = 0.79; CLs: 0.72, 0.85). Overall occupational exposures to particulate matter were low, but results indicate that exposure could exceed the ACGIH®-recommended threshold limit value of 3 mg/m(3) for respirable particulate matter in a few extreme situations. Self-assessed exposure levels agreed with measured concentrations of PM(2.5). Correlation analysis shows that either PM(2.5) or CO could be used as a surrogate measure of exposure to woodsmoke at prescribed burns.

Conference summary: International Biomass Smoke Health Effects (IBSHE).

The Centers for Disease Control and Prevention (CDC) and the University of Montana's Center for Environmental Health Sciences (CEHS) co-hosted a conference entitled "International Biomass Smoke and Health Effects" in Missoula, MT, on August 21 and 22, 2007. The goal of this conference was to bring together experts from diverse fields to review the state of the science in several key areas involving biomass smoke research, as well as identify future research directions. Researchers, physicians, and representatives from regulatory agencies from around the country and world met for a cross-disciplinary exploration of many issues related to biomass smoke research. Major topics of discussion included risk assessment, biomarkers of exposure, toxicology and animal study design, health outcomes measures/study design, and communications gaps. In addition to multiple presentations, breakout sessions were focused on identifying future research directions. In this issue of Inhalation Toxicology, we present the findings from each of these breakout sessions in an effort to summarize what is known in these key areas, and to identify those emerging issues in the field of biomass smoke research.

Application of end-exhaled breath monitoring to assess carbon monoxide exposures of wildland firefighters at prescribed burns.

Exposure to the range of combustion products from wildland fires has been demonstrated to cause respiratory irritation and decreased lung function among firefighters. The measurement of carbon monoxide (CO) has been previously shown to be highly correlated with the range of contaminants found in wildland fires. In this article, we assess the feasibility of using a simple, noninvasive biological test to assess exposure to CO for a group of wildland firefighters. Measurements of CO exposure were collected using personal monitors as well as in exhaled breath for wildland firefighters who conducted prescribed burns in February-March 2004. Overall, the CO concentrations measured in this study group were low with a shift mean of 1.87 ppm. Correspondingly, the cross-shift difference in carboxyhemoglobin as estimated from exhaled breath CO levels was also low (median increase =+0.2% carboxyhemoglobin). The use of exhaled breath measurements for CO has limitations in characterizing exposures within this worker population.