Gm and Km alleles in two Spanish Pyrenean populations (Andorra and Pallars Sobirà): a review of Gm variation in the Western Mediterranean basin

Two Spanish eastern Pyrenean populations, Andorra and Pallars Sobirà, have been tested for G1m(1,2,3,17), G2m(23), G3m(5,6,10,11,13,14,15,16,21,24,28) and Km(1) immunoglobulin allotypes. Km allele and Gm haplotype frequencies in both samples fit well into the Western Mediterranean and, more strictly, Pyrenean ranges with some peculiarities: Andorra showed an elevated frequency (14.7%) of the typical Asian and European Gm21,28;1,2,17;. haplotype, while Pallars Sobirà was characterized by high values (3.7%) of Gm5*;1,17;., a typical sub-Saharan Gm haplotype. Gm diversity assessed through genetic distance and variance analyses revealed a significant geographic partition (4.3%) of Mediterraneans among south, north-east, and north-west groups. It is interesting to note the relatively low genetic variance (2.1%) found between south and north-western Mediterraneans that could reflect ancient population relationships. More locally, genetic boundaries and diversity analyses failed to indicate any geographic pattern and/or genetic differentiation related with the political border in the Pyrenees. The present pattern of variation in this area is probably the result of genetic isolation processes, in addition to some specific demographic phenomena, in the Pyrenean valleys.

[Substitution indexes in ambulatory surgery: measure, count and compare]

OBJECTIVE

Compare the substitution indexes of the ambulatory surgery activity done in the Vall d'Hebron Hospital with those indexes obtained from the all public hospitals of Catalonia which constitute the Public Hospital Net.

METHODS

There have been calculated the substitution indexes of the 65% of DRGs which are treated with ambulatory surgery at the Vall d'Hebron Hospital and in the global of public hospital net in Catalonia. For this purpose, it has been used the MBDS of the years 1998 and 1999. The means of the substitution indexes have been compared with a Z test.

RESULTS

The means of the substitution indexes are of a 48.88% for the Vall d'Hebron Hospital and of a 35.14% for the whole public hospitals. The difference is statically significant (p < 0.0001). Moreover, the highest substitution indexes are the same for both groups and are the follow: 039, 229,364, 262, 062, 362 y 342.

CONCLUSIONS

Taking into account the present techniques of benchmarking in the health care field, this work shows that the substitution indexes are a valid tool that can be used to compare hospitals, specially in the case that it could be possible to work with robust data bases.

Estimated prevalence of noise-induced hearing threshold shifts among children 6 to 19 years of age: the Third National Health and Nutrition Examination Survey, 1988-1994, United States

OBJECTIVE

This analysis estimates the first nationally representative prevalence of noise-induced hearing threshold shifts (NITS) among US children. Historically, NITS has not been considered a common cause of childhood hearing problems. Among children, NITS can be a progressive problem with continued exposure to excessive noise, which can lead to high-frequency sound discrimination difficulties (eg, speech consonants and whistles).

METHODS

The Third National Health and Nutrition Examination Survey (NHANES III) was conducted from 1988 to 1994. NHANES III is a national population-based cross-sectional survey with a household interview, audiometric testing at 0.5 to 8 kHz, and compliance testing. A total of 5249 children aged 6 to 19 years completed audiometry and compliance testing for both ears in NHANES III. The criteria used to assess NITS included audiometry indicating a noise notch in at least 1 ear.

RESULTS

Of US children 6 to 19 years old, 12.5% (approximately 5.2 million) are estimated to have NITS in 1 or both ears. In the majority of the children meeting NITS criteria, only 1 ear and only 1 frequency are affected. In this analysis, all children identified with NITS passed compliance testing, which essentially rules out middle ear disorders such as conductive hearing loss. The prevalence estimate of NITS differed by sociodemographics, including age and sex.

CONCLUSIONS

These findings suggest that children are being exposed to excessive amounts of hazardous levels of noise, and children's hearing is vulnerable to these exposures. These data support the need for research on appropriate hearing conservation methods and for NITS screening programs among school-aged children. Public health interventions such as education, training, audiometric testing, exposure assessment, hearing protection, and noise control when feasible are all components of occupational hearing conservation that could be adapted to children's needs with children-specific research.

The complete genomic sequence of a BLV strain from a Holstein cow from Argentina

DNA was extracted from the peripheral blood of a seropositive, PCR-positive, BLV-infected Holstein cow (No. 38) from Argentina. The DNA was amplified via PCR with a series of overlapping primers encompassing the entire BLV proviral DNA. The amplified BLV ARG 38 DNA was cloned, sequenced, and compared phylogenetically to three other full-length BLV sequences. Characterization of its deduced proteins and its relationship to other members of the PTLV/BLV genus of retroviruses are discussed.

Comparative performances of an HTLV-I/II EIA and other serologic and PCR assays on samples from persons at risk for HTLV-II infection

BACKGROUND

HTLV-I and HTLV-II are related exogenous pathogenic human retroviruses. Until recently, ELISAs based on HTLV-I antigens have been used to screen for the presence of HTLV-I or -II antibodies. The HTLV-I-based assays have not been as sensitive in detecting antibodies to HTLV-II as in detecting antibodies to HTLV-I. The Abbott HTLV-I/HTLV-II ELISA uses a combination of HTLV-I and HTLV-II antigens to detect antibodies to the whole HTLV group. The performance of this ELISA was compared to that of several HTLV-I-based serologic assays and an HTLV-II PCR assay in cohorts of South American Indians and New York City IV drug users (IVDUs) in whom HTLV-II is endemic.

STUDY DESIGN AND METHODS

Sera from 429 South American Indians and New York City IVDUs were evaluated for HTLV antibodies by the use of three ELISAs (rgp21-enhanced HTLV-I/II, Cambridge Biotech; Vironostika HTLV-I/II, Organon Teknika; and HTLV-I/HTLV-II, Abbott), and a Western blot (WB) assay. Peripheral blood leukocyte DNA from each person was analyzed for HTLV-I and HTLV-II pol DNA via PCR. The HTLV-II PCR-positive samples were further subtyped via cloning and sequencing and/or oligomer restriction.

RESULTS

Two hundred four samples (48%) were positive for HTLV-II by serologic and/or PCR assays. All of the positive samples from the Indians and approximately one-third of the positive samples from the IVDUs were of the HTLV-IIB subtype. Comparative analyses indicate that the sensitivity and specificity of the various assays were: PCR, 98 and 100 percent; Abbott HTLV-I/HTLV-II, 78 and 95 percent; Cambridge Biotech HTLV-I/II, 76 and 96 percent; Vironostika HTLV-I/II, 71 and 98 percent; and WB, 73 and 100 percent, respectively.

CONCLUSION

There were no significant differences among the sensitivities and specificities of the HTLV-I/II ELISAs (p values, 0.056-0.438). The WB and PCR assays were much more specific than the other serologic assays (p</=0.03). However, the PCR assay is significantly (p<0.001) more sensitive than any of the serologic assays in the detection of HTLV-II infection. Thus, optimal detection of HTLV-II infection would seem to require both serologic and DNA PCR assays.

A phase II trial of cyclophosphamide, epirubicin and vinorelbine in the treatment of advanced breast cancer

BACKGROUND

Vinorelbine (Navelbin; N) has proven to be active in patients with advanced breast cancer (ABC) and cyclophosphamide (C) and epirubicin (Epiadriamycin: E) are still among the main cytostatic agents against this tumor. On this basis was carried out a study to determine the activity and toxicity of the combination of these three agents (CEN).

PATIENTS AND METHOD

From April 1996 to March 1998, 59 patients with ABC were recruited of whom 56 were found eligible and evaluable for toxicity and 55 for activity. The treatment regimen was C: 400 mg/m2, E: 30 mg/m2 and N: 25 mg/m2 administered intravenously on days 1 and 8 of a 28-day cycle.

RESULTS

The median number of cycles administered was 6 (range: 1-16). The most common hematological toxicity was grade (G) 3 and 4 neutropenia occurring in 36% of patients, associated with fever in 7% of them. Grade 3-4 thrombocytopenia and anemia occurred in 5% and 7%, respectively. Other G2-G3 non hematologic toxicities were: N/vomiting in 34%, alopecia in 73% and mucositis in 11% of patients. An objective response was achieved in 28 of 56 patients (50%) (95% confidence interval (CI): 37-63%): complete response (CR) in 9%, partial response (PR) in 41%. The median duration of response, time to progression and overall survival time was 54, 47 and 90 weeks, respectively.

CONCLUSION

The CEN combination at these doses and treatment schedule appears to have acceptable tolerability but there is no apparent improvement in therapeutic efficacy when compared to other regimens used as first line treatment in ABC.

Lack of BLV and PTLV DNA sequences in the majority of patients with large granular lymphocyte leukaemia

The primate T-cell lymphoma/leukaemia viruses (PTLV) and bovine leukaemia virus (BLV) comprise a unique genus of retroviruses, infection with which induces seroreactivity in the host against conserved epitopes in their p24 gag and gp21 env cognate proteins. Herein, we have confirmed this serocrossreactivity. Patients with large granular lymphocyte (LGL) leukaemia have frequent seroreactivity to the p24 and gp21 env proteins of human T-cell lymphoma/leukaemia virus I (HTLV-I), one of the species in the genus. However, only a small minority of patients are actually infected with prototypic HTLV-I or HTLV-II, another species within the group. In an attempt to determine whether LGL leukaemia might be associated with other members of the PTLV/BLV genus, we examined the peripheral blood mononuclear cell DNA of 22 HTLV p24 and/or gp21 seropositive LGL leukaemia patients via PCR using degenerate and specific primer pair/probe systems capable of detecting all known members of the PTLV/BLV genus. None of the samples was positive. These data indicate that although HTLV-II may be associated with some cases of LGL leukaemia most patients are not infected with a PTLV or BLV virus.

Sp family of transcription factors is involved in iron-induced collagen alpha1(I) gene expression

The purpose of this study was to identify the cis-acting elements and the trans-acting factors involved in the iron-induced expression of the collagen alpha1(I) (COL1aI) gene. Rat hepatic stellate cells were cultured in the presence of 50 microM ferric chloride, 50 microM ascorbic acid, and 250 microM citric acid (Fe/AA/CA), and the effects on collagen gene expression and the binding of nuclear proteins to the COL1aI promoter were measured. The Fe/AA/CA treatment induced a time- and dose-dependent increase in the cellular levels of COL1aI mRNA that was abrogate by pretreating cells with cycloheximide, antioxidants, and inhibitors of aldehyde-protein adduct formation. Transient transfection experiments showed that Fe/AA/CA exerted its effect through regulatory elements located between -220 and -110 bp of the COL1aI promoter. Gel retardation assays showed that Fe/AA/CA increased the binding of nuclear proteins to two elements located between -161 and -110 bp of the COL1aI promoter. These bindings were blocked by unlabeled consensus Sp1 oligonucleotide and supershifted with Sp1 and Sp3 antibodies. Finally, Fe/AA/CA increased cellular levels of the Sp1 and Sp3 proteins and Sp1 mRNA. Treatment with Fe/AA/CA stimulates COL1aI gene expression by inducing the synthesis of Sp1 and Sp3 and their binding to two regulatory elements located between -161 and -110 bp of the COL1aI promoter.

Boron and calcium distribution in nitrogen-fixing pea plants

In a glasshouse experiment, plants of Pisum sativum L. cv. Argona were grown hydroponically with different B and Ca levels, in order to elucidate a specific role for B and Ca on the N(2) fixation in this temperate legume. The treatments were as follows: control (9.3 µM B and 2 mM Ca), -B (without B and 2 mM Ca), -B+Ca (without B and 3.6 mM Ca), +Ca (9.3 µM B and 3.6 mM Ca), -Ca (9.3 µM B and 0.4 mM Ca) and -Ca+B (46.5 µM B and 0.4 mM Ca). The supply of -Ca and +Ca did not affect nitrogenase activity, but the weight of old shoots and total N content increased with the Ca treatment. No symptoms of B deficiency were detected in the plants of the -B and -B+Ca treatments, apart from weight reduction in young shoots and lower nitrogenase activity. The B concentration decreased in young shoots and roots of plants grown without B (-B), but there was a sharper decrease in the roots of -B+Ca plants and the levels of B in the young shoots were similar to the control levels. The B concentration in -Ca plants was reduced in the old shoot and in the root, while plant weight and N content increased in -Ca+B plants. The cell wall and total B concentrations in the nodules were 4-fold compared with those of the roots. By contrast, the Ca root wall was 2.5 times higher than the nodule levels although total pectin was higher in the nodule than in the root. Finally, the results obtained showed that a high supply of Ca could induce B mobilisation from root to shoot. On the other hand, the high B requirement found in pea plant nodules may contribute to explain the low nitrogenase activity detected under -B conditions.

Tumor markers at the time of recurrence in patients with germ cell tumors

BACKGROUND

alpha-fetoprotein (AFP), human chorionic gonadotropin (HCG), and lactate dehydrogenase (LDH) closely follow the course of germ cell tumors (GCTs) and are widely used for diagnosis, prognosis, and follow-up purposes. The objective of this study was to assess the concordance of tumor markers at the time of diagnosis and recurrence.

METHODS

The authors reviewed the records of 794 patients with GCTs treated in three Spanish hospitals from 1977-1996 and analyzed the concordance between AFP, HCG, and LDH levels at diagnosis and first and second recurrence. A positive marker was defined as a level of AFP > 10 ng/mL, HCG > 5 IU/L, or LDH > the upper limit of normal. One hundred twenty-five patients were identified who developed a first recurrence (123 had marker levels recorded). The median age was 27 years (range, 14-78 years). Histology was seminoma in 36 patients (29%) and nonseminomatous GCT (NSGCT) in 87 patients (71%).

RESULTS

Seventy-nine patients (64%) had elevated tumor markers at diagnosis and 76 (62%) at first recurrence. An elevated marker was present at first recurrence in 58 of 79 patients (73%) with initially positive markers and in 18 of 44 patients (41%) with initially negative markers. In 84 of 123 patients (68%), the same marker pattern (positive or negative) was present at the time of diagnosis and at first recurrence, 78% in seminomas and 64% in NSGCTs. The earliest indicator of recurrence was an elevated marker in patients with NSGCTs and a radiologic finding in patients with seminomas. Thirty patients developed a second recurrence, 27 of whom (90%) had the same marker pattern as at first recurrence.

CONCLUSIONS

Tumor marker pattern at diagnosis is not a good predictor of the pattern at recurrence, particularly in patients with NSGCTs. Marker assessment should be included in the follow-up schedule regardless of levels at the time of diagnosis. Early detection of recurrence should not rely only on marker levels, even in patients with elevated levels at presentation.

Hair and blood as substrates for screening children for lead poisoning

In Russia, hair, rather than blood, is usually used as a substrate for screening children for lead poisoning. We attempted to gauge the accuracy of this method by comparing these two methods. The evaluation was done in Saratov, Russia. We collected hair and blood samples from 189 children who attended 11 kindergartens. Their mean blood lead concentration was 9.8 microg/dl (range = 3.1-35.7 microg/dl), and their mean hair lead concentration was 7.2 microg/g (range = 1.0-7.2 microg/g [i.e., 1.0 being the lowest detectable limit]). Hair lead concentration as a screening method had 57% sensitivity and resulted in 18% of the children being classified as false-negatives. We conclude, therefore, that measuring hair lead concentration is not an adequate method with which to screen children for lead poisoning.

Genetic relationships between southeastern Spain and Morocco: New data on ABO, RH, MNSs, and DUFFY polymorphisms

The genetic polymorphism of four blood group systems (ABO, RH, MNSs, and DUFFY) was analyzed in two well-defined population samples coming from south-central Morocco and southeastern Spain. Both a controversial ancient common substrate and the long period of coexistence between North Africa and southern Spain during the eight centuries of the Islamic invasion of the Iberian Peninsula suggest a particular genetic relationship between northwestern Africa and southern Spain. Allele distributions in each sample are in general agreement with that expected according to the geographical and historical characteristics in the Mediterranean region. However, the differences between the Moroccan sample and other north African groups illustrate considerable genetic variability in this geographical region. In comparison with other samples from different regions of the Iberian Peninsula, the markers examined fail to demonstrate any particular affinity between the southern Spanish sample of La Alpujarra and Moroccan populations. Am. J. Hum. Biol. 11:745-752, 1999. Copyright 1999 Wiley-Liss, Inc.

Red cell enzyme polymorphisms in Moroccans and southern Spaniards: new data for the genetic history of the western Mediterranean

Population samples from Morocco (El Jadida, south Atlantic coast) and La Alpujarra (Granada mountains, Spain), located on both shores of the western Mediterranean, were typed for 8 erythrocyte genetic markers: ACP1, ESD, PGD, AK1, GLO1, PGM1, SODA, and DIA. Genetic heterogeneity within western Mediterranean groups was investigated on the basis of allele frequencies of these 8 polymorphisms plus ABO and Rh (CDE). Only slight peculiarities for the ACP1, GLO1, and AK1 systems were observed in the 2 samples compared with other Mediterranean data. The new data are consistent with a main north to south genetic differentiation in the Mediterranean region. However, with regard to other European groups, the La Alpujarra population shows a particular affinity with North Africans that may be compatible with both an ancient common substratum and/or a special historical influence during the Muslim domination of the Iberian Peninsula.

A fertile amphiploid between diploid wheat (Triticum tauschii) and crested wheat grass (Agropyron cristatum)

Alloploidy, one of the most efficient evolutionary mechanisms in nature, has not been extensively exploited in plant breeding programmes. Many genomic combinations remain to be created by plant breeders, to be used directly as new crops or indirectly to widen the genetic basis of crops. The Triticeae tribe, to which wheat belongs, is among the botanical groups in which this strategy has been successfully explored. However, there remain valuable genomic combinations that have not been obtained at the diploid level. The Agropyron complex (wheat-grasses) has recently been the focus of attention for interspecific hybridization, but intergeneric hybrids or amphiploids with wheat have not been reported at the diploid level. Here we report synthesis of a tetraploid amphiploid between Triticum tauschii and Agropyron cristatum by crossing two tetraploid accessions. Using total genome in situ hybridization (GISH) staining on metaphase I pollen mother cells, data on allosyndetic and autosyndetic chromosome pairing have been obtained. These data support the view that the A. cristatum tetraploid parent used in the synthesis of the amphiploid has a segmental alloploidy nature.

A fertile amphiploid between diploid wheat (Triticum tauschii) and crested wheatgrass (Agropyron cristatum)

Alloploidy, one of the most efficient evolutionary mechanisms in nature, has not been extensively exploited in plant breeding programmes. Many genomic combinations remain to be created by plant breeders, to be used directly as new crops or indirectly to widen the genetic basis of crops. The Triticeae tribe, to which wheat belongs, is among the botanical groups in which this strategy has been successfully explored. However, there remain valuable genomic combinations that have not been obtained at the diploid level. The Agropyron complex (wheat-grasses) has recently been the focus of attention for interspecific hybridization, but intergeneric hybrids or amphiploids with wheat have not been reported at the diploid level. Here we report synthesis of a tetraploid amphiploid between Triticum tauschii and Agropyron cristatum by crossing two tetraploid accessions. Using total genome in situ hybridization (GISH) staining on metaphase I pollen mother cells, data on allosyndetic and autosyndetic chromosome pairing have been obtained. These data support the view that the A. cristatum tetraploid parent used in the synthesis of the amphiploid has a segmental alloploidy nature.

Endemic Trypanosoma cruzi infection in Indian populations of the Gran Chaco territory of South America: performance of diagnostic assays and epidemiological features

The relative specificities and sensitivities of several serological assays for the diagnosis of Trypanosoma cruzi infection were estimated in Indian populations of Argentina and Paraguay. The results obtained with the assays, which proved to be most reliable, were used to study the distribution of the parasite in these populations. Serological evidence of T. cruzi infection was demonstrated in 256 (37.7%) of 679 Indians living in relatively small and isolated communities in the Salta province of northern Argentina and in western Paraguay, regions that are part of the tropical territory called Gran Chaco. In contrast, none of the 94 Indians examined in south-western Argentina was positive. Infection in the Gran Chaco Indians increased with age and clustered in families. Marked differences in seroprevalence were observed between the 16 Indian communities examined in Gran Chaco. These differences seem to be associated both with the risk of transmission from the sylvatic reservoirs of the parasite and with the frequency with which vector-spraying campaigns have been implemented.

High prevalence of hantavirus infection in Indian communities of the Paraguayan and Argentinean Gran Chaco

Serologic evidence of past infection with a Sin Nombre-like hantavirus(es) was demonstrated in 78 (40.4%) of 193 Indians living in western Paraguay and in 38 (17.1%) of 222 Indians inhabiting the Salta province of northern Argentina. In both populations seroprevalence increased with age, with the most striking increase occurring at 18 years of age in the Paraguayan population and at 35 years of age in the Salta population. The peak prevalences in both populations (66.6% and 44.0%, respectively) were seen in Indians > 53 years old. Although no sex difference was observed in the Paraguayan Indians, in the Salta population seroprevalence was greater in males than in females. Familiar clustering of the infection was observed. The data indicate that the Indian populations of the Gran Chaco are frequently exposed to and survive infection with a Sin Nombre-like virus(es). Possible explanations of this novel epidemiology are discussed.

Genetic diversity in northern Spain (Basque Country and Cantabria): GM and KM variation related to demographic histories

Genetic diversity in Northern Spain (SW Europe) was assessed through the analysis of the GM and KM immunoglobulin markers in 505 individuals using a set of 17 allotypes, including the G2M(23) allotype which has been infrequently used before now. The individuals were representative of three anthropologically well-defined populations belonging to two geographically and archaeologically distinct areas in the Basque Country (Guipúzcoa and Alava provinces) and to the mountainous region of Montes de Pas in the province of Cantabria. Gene frequency distributions indicated a high genetic divergence between Montes de Pas and the Basque Country, and a relative degree of heterogeneity between the two Basque regions. The genetic differentiation of Montes de Pas, which is consistent with previous classical polymorphism analyses, suggests a considerable genetic variation range within the Iberian Peninsula, possibly higher than that often polarised around the Basque versus non-Basque variation. Analyses of genetic structure show that the major differentiation of Montes de Pas could be related to the historically documented mixed origin of this population. The moderate genetic distances between regions in the Spanish Basque Country could be explained by differential systematic pressures acting through a stronger gene flow in the South than in the more isolated Northern areas. The comparisons with neighbouring populations from the French Pyrenees suggest that the present genetic variation revealed by lg polymorphisms in SW Europe can be related to historical demographic processes including gene flow and/or low population sizes.

Expansion of clonotypic T-cell populations in the peripheral blood of asymptomatic Gran Chaco Amerindians infected with HTLV-IIB

Peripheral blood mononuclear cells from asymptomatic HTLV-II-infected and uninfected Gran Chaco Amerindians were analyzed using polymerase chain reaction (PCR) for expansions of T-cell receptor (TCR) V-beta gene clonotypes. Analyses were performed using primer pairs designed to identify expanded T-cell familial clonotypes based on their unique TCR beta gene rearrangements. Of the 30 HTLV-IIB-positive samples tested, five showed evidence of V-beta clonotypic T-cell expansion. Of the five expansions, two were monoclonotypic and the remaining three were oligoclonotypic. In comparison, 30 HTLV-II-negative Amerindians showed no evidence of clonotypic T-cell expansion. Amplified DNA from one of the monoclonotypic samples was subsequently cloned and sequenced and was found to have uniform variable/ diversity/joining sequences confirming its unique monoclonal T-cell expansion. This method of detecting clonal TCR beta gene rearrangements has the advantage over traditional Southern blot techniques of being more sensitive and specific even with suboptimal specimens. The prognostic significance of clonotypic T-cell expansion in a group such as the HTLV-II-infected Gran Chaco Amerindians remains to be determined.

Prevalence of hearing loss among children 6 to 19 years of age: the Third National Health and Nutrition Examination Survey

CONTEXT

Hearing loss in children influences the development of communication and behavioral skills, but few studies in the United States have used pure-tone audiometry to derive hearing loss prevalence estimates for children.

OBJECTIVE

To describe the prevalence of hearing loss among US children by sociodemographic characteristics, reported hearing loss, and audiometric screening factors.

DESIGN

National population-based cross-sectional survey with an in-person interview and audiometric testing at 0.5 to 8 kHz.

SETTING/PARTICIPANTS

A total of 6166 children aged 6 to 19 years completed audiometry in the mobile examination center of the Third National Health and Nutrition Examination Survey conducted between 1988 and 1994.

MAIN OUTCOME MEASURE

Hearing loss, defined as audiometric threshold values of at least 16-dB hearing level based on a low or high pure-tone average.

RESULTS

A total of 14.9% of children had low-frequency or high-frequency hearing loss of at least 16-dB hearing level, 7.1% had low-frequency hearing loss of at least 16-dB hearing level, and 12.7% had high-frequency hearing loss of at least 16-dB hearing level. Most hearing loss was unilateral and slight in severity (16- to 25-dB hearing level). Of those with measured hearing loss, 10.8% were reported to have current hearing loss during the interview.

CONCLUSIONS

This analysis indicates that 14.9% of US children have low-frequency or high-frequency hearing loss of at least 16-dB hearing level in 1 or both ears. Among children in elementary, middle, and high school, audiometric screening should include low-frequency and high-frequency testing to detect hearing loss.