Occupation versus environmental factors in hypersensitivity pneumonitis: population attributable fraction.

BACKGROUND: Despite well-documented case series of hypersensitivity pneumonitis (HP), epidemiological data delineating relative contributions of risk factors are sparse. To address this, we estimated HP risk in a case-referent study of occupational and nonoccupational exposures. METHODS: We recruited cases of HP by ICD-9 codes from an integrated healthcare delivery system (IHCDS) and a tertiary medical care centre. We drew referents, matched for age and sex, from the IHCDS. Participants underwent comprehensive, structured telephone interviews eliciting details of occupational and home environmental exposures. We employed a hierarchical analytic approach for data reduction based on the false discovery rate method within clusters of exposures. We measured lung function and selected biomarkers in a subset of participants. We used multivariate logistic regression to estimate exposure-associated odds ratios (ORs) and population attributable fractions (PAFs) for HP. RESULTS: We analysed data for 192 HP cases (148 IHCDS; 44 tertiary care) and 229 referents. Occupational exposures combined more than doubled the odds of developing HP (OR 2.67; 95% CI 1.73-4.14) with a PAF of 34% (95% CI 21-46%); nonoccupational bird exposure also doubled the HP odds (OR 2.02; 95% CI 1.13-3.60), with a PAF of 12% (3-21%). Lung function and selected biomarkers did not substantively modify the risk estimates on the basis of questionnaire data alone. DISCUSSION: In a case-referent approach evaluating HP risk, identifiable exposures accounted, on an epidemiological basis, for approximately two in three cases of disease; conversely, for one in three, the risk factors for disease remained elusive.

Role of delta-aminolevulinic acid in the symptoms of acute porphyria.

BACKGROUND: Attacks of neuropathic pain, usually abdominal, are characteristic of the acute porphyrias and accompanied by overproduction of heme-precursor molecules, specifically delta-aminolevulinic acid and porphobilinogen. The basis for the acute symptoms in these diseases has been speculative. METHODS: We review genetic acute porphyria, hereditary tyrosinemia, and an acquired condition, lead poisoning. All perturb heme synthesis and present with a similar pain syndrome. RESULTS: Although each of these conditions has characteristic urine biochemistry, all exhibit excess delta-aminolevulinic acid. Moreover, in all, treatment with hemin reduces delta-aminolevulinic acid and relieves symptoms. In contrast, use of recombinant porphobilinogen deaminase to knock down porphobilinogen in acute porphyria was ineffective. CONCLUSIONS: There is now convincing evidence that delta-aminolevulinic acid is the cause of pain in the acute porphyrias. The efficacy of hemin infusion is due mainly, if not entirely, to its inhibition of hepatic delta-aminolevulinic acid synthase-1, the enzyme that catalyzes delta-aminolevulinic acid formation. Delta-aminolevulinic acid synthase-1 is a rational target for additional therapies to control symptoms in acute porphyria.

Topical antacid therapy for capsaicin-induced dermal pain: a poison center telephone-directed study.

PURPOSE: The study aimed to assess the effects of topical antacids for treatment of capsaicin-induced dermal pain after exposure to capsaicin containing hot peppers, personal protection sprays, or topical creams. PROCEDURES: Participants of the study were California Poison Control System (CPCS) hotline callers 12 years or older with dermal pain from exposure to capsaicin-containing products or plants. Participants were instructed to apply a topical antacid and assessed for perceived pain (using a 0-10 scale) pre- and posttreatment. A positive response was defined as a sustained reduction of pain 33% or more within 30 minutes or achieving a pain score of 0 to 1. MAIN FINDINGS: Of 93 eligible patients, 64 applied antacids and had outcome data available. Patients contacted the CPCS a median of 1 hour postexposure with a median initial pain score of 7.5/10. Thirty-six (56%) were exposed to unrefined (natural) peppers and 28 (44%) to refined capsaicin (eg, capsaicin-containing cream). Before calling the CPCS, 57 (89%) attempted at least one treatment. Forty-five (70%) reported positive response to antacid treatment as a 33% reduction in pain in 30 minutes (n = 17), a reduction in pain to a score of 0 to 1 (n = 3), or both (n = 25). A 33% reduction in pain within 30 minutes was associated with exposure to refined capsaicin (odds ratio, 3.37; 95% confidence interval, 0.98-11.66). Concomitant refined capsaicin exposure and early treatment (<1 hour of symptoms) was associated with even greater odds of response (odds ratio, 5.4; 95% confidence interval, 1.4-21.2). CONCLUSION: Topical application of antacids for capsaicin-induced pain is effective, particularly in early treatment of exposure to refined capsaicin.

Effect of race on asthma management and outcomes in a large, integrated managed care organization.

BACKGROUND: Morbidity from asthma disproportionately affects black people. Whether this excess morbidity is fully explained by differences in asthma severity, access to care, or socioeconomic status (SES) is unknown. METHODS: We assessed whether there were racial disparities in asthma management and outcomes in a managed care organization that provides uniform access to health care and then determined to what degree these disparities were explained by differences in SES, asthma severity, and asthma management. We prospectively studied 678 patients from a large, integrated health care delivery system. Patients who had been hospitalized for asthma were interviewed after discharge to ascertain information about asthma history, health status, and SES. Small-area socioeconomic data were ascertained by means of geocoding and linkage to the US Census 2000. Patients were followed up for subsequent emergency department (ED) visits or hospitalizations (median follow-up, 1.9 years). RESULTS: Black race was associated with a higher risk of ED visits (hazard ratio [HR], 1.93; 95% confidence interval [CI], 1.39-2.66) and hospitalizations (HR, 1.89; 95% CI, 1.30-2.76). This finding persisted after adjusting for SES and differences in asthma therapy (adjusted HR for ED visits, 1.73; 95% CI, 1.07-2.81; and adjusted HR for hospitalizations, 2.01; 95% CI, 1.33-3.02). CONCLUSIONS: Even in a health care setting that provides uniform access to care, black race was associated with worse asthma outcomes, including a greater risk of ED visits and hospitalizations. This association was not explained by differences in SES, asthma severity, or asthma therapy. These findings suggest that genetic differences may underlie these racial disparities.

An evaluation of selected herbal reference texts and comparison to published reports of adverse herbal events.

OBJECTIVE: There has been a recent proliferation of medical reference texts intended to guide practitioners whose patients use herbal therapies. We systematically assessed six herbal reference texts to evaluate the information they contain on herbal toxicity. METHODS: We selected six major herbal references published from 1996 to 2000 to evaluate the adequacy of their toxicological information in light of published adverse events. To identify herbs most relevant to toxicology, we reviewed herbal-related calls to our regional California Poison Control System, San Francisco division (CPCS-SF) in 1998 and identified the 12 herbs (defined as botanical dietary supplements) most frequently involved in these CPCS-SF referrals. We searched Medline (1966 to 2000) to identify published reports of adverse effects potentially related to these same 12 herbs. We scored each herbal reference text on the basis of information inclusiveness for the target 12 herbs, with a maximal overall score of 3. RESULTS: The herbs, identified on the basis of CPCS-SF call frequency were: St John's wort, ma huang, echinacea, guarana, ginkgo, ginseng, valerian, tea tree oil, goldenseal, arnica, yohimbe and kava kava. The overall herbal reference scores ranged from 2.2 to 0.4 (median 1.1). The Natural Medicines Comprehensive Database received the highest overall score and was the most complete and useful reference source. All of the references, however, lacked sufficient information on management of herbal medicine overdose, and several had incorrect overdose management guidelines that could negatively impact patient care. CONCLUSION: Current herbal reference texts do not contain sufficient information for the assessment and management of adverse health effects of botanical therapies.