Rodolfo Rivas-Ruiz

Hearing loss in Mexican children treated with cisplatin.

OBJECTIVEnCisplatin is widely used to treat a variety of pediatric solid tumors. One of the most severe and debilitating adverse drug reactions experienced by patients who receive cisplatin therapy is permanent bilateral hearing loss. The aim of this study was to evaluate the incidence and risk factors for cisplatin-induced hearing loss in Mexican pediatric patients.nnnMETHODSnDetailed medical and drug histories, including use of cisplatin as well as other drugs known to cause hearing loss, were collected from patient medical records. Results of audiology tests on pediatric patients with solid tumors were collected at baseline, during treatment and at the end of cisplatin chemotherapy. Hearing loss was classified according to the Common Terminology Criteria for Adverse Events. Bivariate and multivariate analyses were performed using survival curves.nnnRESULTSnFifty-nine pediatric patients, median age 11 years (range, 3-17 years) were included in the study. The incidence of cisplatin-induced hearing loss was 56%. Individual risk factors including age (< 5 years), male sex, and concomitant medications were not associated with an increased risk of cisplatin-induced hearing loss. Patients with a diagnosis of osteosarcoma and a cumulative cisplatin dose greater than 400 mg/m(2) were at higher risk of hearing loss compared with all other tumor and cumulative dose combinations (HR = 2.47 [95% CI, 1.043-5.831]).nnnCONCLUSIONSnCumulative dose and tumor type are associated with an increased risk of cisplatin-induced hearing loss. Further research is required to characterize fully the interindividual variation in hearing loss in Mexican patients.

High prevalence of hypovitaminosis D in Mexicans aged 14 years and older and its correlation with parathyroid hormone

SummaryA sample of 585 healthy subjects 14xa0years and older was studied to estimate the status of 25-hydroxyvitamin D (25(OH)D) and its correlation with parathyroid hormone in healthy Mexicans. In 43.6xa0% of the sample, levels of vitamin D were below 20xa0ng/mL and showed an inverse relationship with parathyroid hormone (PTH; pu2009<u20090.01).PurposeThe purpose of the present study was to estimate the status of 25-hydroxyvitamin D (25(OH)D) and its correlation with parathyroid hormone in healthy Mexicans.MethodsA cross-sectional study of 585 healthy subjects 14xa0years and older was carried out. A questionnaire including all relevant demographics, medical history, and lifestyle factors was applied by trained interviewers. Morning fasting blood was collected in all subjects for estimation of 25(OH)D using liquid chromatography-tandem mass spectrometry and PTH hormone–intact molecule by RIA.ResultsOf the group of 585 subjects, 54.1xa0% were women; the sample was divided in three age groups (14–29, 30–50, and >51). Only 9.6xa0% of the total sample had levels of 25(OH)D above 30xa0ng/mL; 46.8xa0% were between 20 and 29xa0ng/mL, and 43.6xa0% were below 20xa0ng/mL. Regarding PTH, a three-phase model was identified using regression smoothing scatterplot (LOESS), with two thresholds of 25(OH)D of 19 and 29xa0ng/mL. Phase 1 (25(OH)D <19xa0ng/mL) showed an inverse relationship with PTH (pu2009<u20090.01); phases 2 and 3 showed no significant relationship.ConclusionOur results show that 43.6xa0% of the Mexicans in this study have deficient concentration levels of vitamin D. The cutoff point of 20xa0ng/mL of 25(OH)D established by the Institute of Medicine has a biological and statistically significant relationship with PTH levels in the Mexican population, independently of principal confounding factors. Like many other countries, Mexico could be included in the global epidemic of hypovitaminosis D.

Bone Speed of Sound Throughout Lifetime Assessed With Quantitative Ultrasound in a Mexican Population

The purpose of this study was to assess the bone speed of sound (SoS) through lifetime of a large Mexican population sample by determining the SoS from the radius and tibia using quantitative ultrasound (QUS). This is a cross-sectional evaluation of participants in the Mexican Health Workers Cohort Study. QUS measurements were performed using Sunlight Omnisense 8000P; Z- and T-scores were calculated for both sexes at the distal third of the radius and midshaft tibia, both on the nondominant side. A locally weighted regression smoothing scatterplot model was used to identify different phases of bone accretion and loss. A total of 9128 participants aged 1-75 yr were measured with QUS. Bone SoS accretion began 5 yr earlier in girls than boys (p<0.05). Maximal SoS or peak bone SoS was noted at 28 yr in the radius and at 22 yr in the tibia. Postmenopausal women (45-50 yr) showed significant SOS decrease at both sites (p<0.05) compared with men. Using the locally weighted regression smoothing scatterplot model, we found 5 different phases that constitute the biological development of bone over the life course, from ages 1-6, 7-12, 12-25, 25-50, and 50-75 yr (p<0.05). Our study shows the age- and sex-dependent changes and different phases of bone development expressed by SoS measurements of the radius and tibia. The values reported in this study can be used as a reference for urban Mexican population.

Comparison of International Reference Values for Bone Speed of Sound in Pediatric Populations: Meta-analysis

The aim of this study was to compare international reference values (RV) for tibial and radial speed of sound (SoS) assessed by quantitative ultrasound (QUS) in pediatric populations. These values were compared by age and country of origin in a systematic review with meta-analysis from studies published on QUS (Sunlight Omnisense). A search was carried out in electronic databases. Nine studies with 6963 patients were included in the meta-analysis. For the newborn populations, 3 studies (from Italy, Portugal, and Israel) were used. These studies included subjects with 27-42 wk gestational age. The mean difference (Portugal-Israel) was found to be 23.62xa0m/s [95% confidence interval [CI] 6.29, 40.95]. Additionally, no difference was found between Italy-Portugal (pxa0=xa00.69), or Italy-Israel (pxa0=xa00.28). In pediatric populations, we compared 8 studies from Canada, Mexico, Israel, Greece, Portugal, and Turkey. No significant differences found for SoS RV between Israel-Turkey, Israel-Greece, or Israel-Canada (pxa0>xa00.05). Significant differences were found in Mexico-Israel -105.29xa0m/s (95% CI -140.05, -70.54) (pxa0<xa00.001); Mexico-Portugal -115.14xa0m/s (95% CI -164.86, -65.42) (pxa0<xa00.001); Mexico-Greece: -239.14xa0m/s (95% CI -267.67, -210.62) (pxa0<xa00.001); Mexico-Turkey: -115.14xa0m/s (95% CI -164.86, -65.42) (pxa0<xa00.001); Mexico-Canada: -113.51xa0m/s (95% CI -140.25, -86.77) (pxa0<xa00.001).This study demonstrates that there are differences in SoS-RV obtained by tibial and radial QUS in pediatric populations between Mexico and other countries (Israel, Portugal, Greece, Turkey, and Canada).