ABSTRACT
We measured fingernail metal levels, Békésy-type pure-tone thresholds and distortion product otoacoustic emission (DPOAE) levels in 59 subjects residing in the gold mining community of Bonanza, Nicaragua. Auditory testing revealed widespread hearing loss in the cohort. Nail metal concentrations (mercury, lead, aluminum, manganese and arsenic) far exceeded reference levels. No relationship was found between metal levels and auditory test results for the group as a whole. Statistically significant relationships were found between DPOAE response amplitudes and metal concentrations in a subgroup with less than 40 h per week of significant noise exposure; however, conclusions regarding these relationships should be tempered by the large number of analyses performed. Several young individuals with high metal levels reported neurological symptoms and had poor hearing. The data suggest that metal levels in artisanal mining communities present a significant public health problem and may affect hearing.
Subject(s)
Hearing Loss/diagnosis , Hearing Loss/epidemiology , Mining/statistics & numerical data , Poisoning/epidemiology , Adolescent , Adult , Aged , Aluminum/toxicity , Arsenic/toxicity , Audiometry, Pure-Tone , Auditory Threshold , Child , Female , Heavy Metal Poisoning , Humans , Lead/toxicity , Male , Manganese/toxicity , Mercury/toxicity , Middle Aged , Nails , Nicaragua/epidemiology , Noise/adverse effects , Otoacoustic Emissions, Spontaneous , Surveys and Questionnaires , Young AdultABSTRACT
Mortality or incidence rates of ten major neoplasms in migrants from several countries, their respective countries of origin, their American-born offspring, and United States whites were compared. Rates in succeeding generations of Americans increased most rapidly for colon cancer and most slowly for breast cancer, with ovarian cancer occupying an intermediate position and prostate cancer showing inconsistent patterns of displacement of rates among various ethnic groups. Rates of stomach, liver, and esophageal cancers declined rapidly in succeeding generations of migrants, although small residual excess risks compared to whites persisted in second generation Americans. These residual excesses were greatest for stomach cancer and least for cancer of the esophagus. Differences in rates of lung and bladder cancers were commensurate with differences in smoking patterns among the generations and ethnic groups considered. This was also true for pancreatic cancer in Asians, but not in Latin Americans. The etiological implications of these observations are discussed.