Metabolic consequences of snoring in adolescents and younger adults: a population study in Chile.

STUDY OBJECTIVES: To investigate the potential association between snoring and other symptoms indicative of sleep-disordered breathing and metabolic syndrome (MetS) in Hispanic adolescents and younger adults using a large population-based survey. METHODS: Sleep-related information, anthropometric measurements and fasting blood samples markers of MetS were obtained from subjects aged 15-40 years collected through the 2nd Chilean Health Survey. Regression models were constructed to evaluate the associations of snoring with MetS, hypertension and serum cholesterol levels. The modulating effect of sleep duration was accounted for in the models. RESULTS: A total of 2147 subjects (42% males, mean age 27.9±7.6 years) were included. Snoring and short sleep duration were present in 43.5 and 25% of the entire population, respectively. MetS was detected in 19.5% of the subjects. In the adjusted regression model, the odds of MetS among snoring subjects were 2.13 times higher (95% confidence interval (CI): 1.52-2.99; P<0.01), and 1.53-fold higher odds of elevated cholesterol also emerged (95% CI: 1.12-2.10; P<0.01). However, the odds of hypertension were not increased by the presence of snoring after adjusting for confounders. In addition, snoring was associated with an increase of 7.26 and 6.56 mg dl-1 for total and low-density lipoprotein cholesterol, respectively, even after adjusting for age, sex and body mass index. Short sleep duration was associated with a small albeit significant risk increase for high systolic blood pressure. CONCLUSIONS: In this large population-based sample of young Hispanic adults and adolescents, snoring, but not sleep duration, emerged as an independent risk factor for dyslipidemia and MetS, but not for hypertension.

Genetic analysis of Hispanic individuals with cystic fibrosis.

We have performed molecular genetic analyses of Hispanic individuals with cystic fibrosis (CF) in the southwestern United States. Of 129 CF chromosomes analyzed, only 46% (59/129) carry delta F508. The G542X mutation was found on 5% (7/129) of CF chromosomes. The 3849 + 10kbC-->T mutation, detected primarily in Ashkenazi Jews, was present on 2% (3/129). R1162X and R334W, mutations identified in Spain and Italy, each occurred on 1.6% (2/129) of CF chromosomes. W1282X and R553X were each detected once. G551D and N1303K were not found. Overall, screening for 22 or more mutations resulted in detection of only 58% of CF transmembrane conductance regulator gene mutations among Hispanic individuals. Analysis of KM19/XV2c haplotypes revealed an unusual distribution. Although the majority of delta F508 mutations are on chromosomes of B haplotypes, the other CF mutations are on A and C haplotypes at higher-than-expected frequencies. These genetic analyses demonstrate significant differences between Hispanic individuals with CF and those of the general North American population. Assessment of carrier/affected risk in Hispanic CF individuals cannot, therefore, be based on the mutation frequencies found through studies of the general population but must be adjusted to better reflect the genetic makeup of this ethnic group. Further studies are necessary to identify the causative mutation(s) in this population and to better delineate genotype/phenotype correlations. These will enable counselors to provide more accurate genetic counseling.

Incidence of sudden infant death syndrome in infants with sickle cell trait.

The significantly higher incidence of both sickle cell trait (SCT) and sudden infant death syndrome (SIDS) in the black population suggests that SCT and SIDS may be epidemiologically related. To study this possibility, we identified, for the period of February 1990 to February 1992, all infants with SCT born in Los Angeles County whose disease was diagnosed through the California Newborn Screening Program. We matched these infants with all confirmed cases of SIDS in Los Angeles County from February 1990 to March 1993. Three cases of SCT among 589 infants confirmed to have had SIDS were identified. The incidence of SIDS was 1.25/1000 live births for the general population versus 0.58/1000 cases for the SCT group. This finding remained unchanged when rates were adjusted for ethnicity. We conclude that infants born with SCT are not at increased risk of dying of SIDS.

Recurrent apparent life-threatening events during infancy: a manifestation of inborn errors of metabolism.

To determine how often inborn errors of metabolism may cause unexplained apnea or recurrent apparent life-threatening events in infants, we retrospectively reviewed the records of 166 infants who were referred for apnea evaluation. A metabolic disorder was identified in 7 infants (4.2%), all of whom had recurrent apparent life-threatening events.

Prevalence of medium-chain acyl-coenzyme A dehydrogenase deficiency in the sudden infant death syndrome.

Disorders of fatty acid beta-oxidation have been suggested as playing a significant role in the sudden infant death syndrome (SIDS). To elucidate the role of medium-chain acyl-coenzyme A dehydrogenase (MCAD) deficiency in SIDS, we identified all cases of SIDS occurring in Los Angeles County between January 1986 through December 1991. A total of 1304 SIDS deaths were identified; tissue samples were collected in 1236 cases (94.8%). Extraction of DNA was successful in 1224 tissue samples (93.9%), which were examined for the presence of the G985 mutation, identified as occurring in more than 88% of affected cases of MCAD deficiency. Three heterozygotes and no homozygotes were identified; this incidence does not differ from that reported in the general population. Review of the pathologic specimens from the identified heterozygotes and from 18 ethnic-, age-, and sex-matched control subjects revealed significant fatty infiltration of all organs examined in one of the three heterozygotes and in none of the control subjects. We conclude that MCAD deficiency does not play a significant role in the causation of SIDS.

Anthropometric measurements in a newborn population in west Africa: a reliable and simple tool for the identification of infants at risk for early postnatal morbidity.

The predictive value of anthropometric measurements in the identification of infants at risk for early postnatal morbidity was assessed in a cohort of 490 neonates born in Yaoundé, Cameroon. Mid-arm circumference (MAC), head circumference, weight, and length were measured within 6 hours of birth, and the gestational age, individual MAC/head circumference ratio, and individual ponderal index were calculated. A detailed questionnaire on gestational medical history was also obtained from the mothers. All infants were then closely monitored during the first 72 hours after delivery for the appearance of symptoms requiring medical intervention and treated accordingly. Low birth weight (LBW) was observed in 37.75%, prematurity in 25.5%, and small size for gestational age in 14.1% of the neonates. Gestational medical problems were reported by 44.3% of the mothers; malaria was the most frequent. Early postnatal morbidity was observed in 26% of the infants; infection (53%), respiratory distress (26%), hypoglycemia (26%), and convulsions (11.7%) accounted for most of the problems. The MAC correlated best of all variables with birth weight (r = 0.91); a value of less than or equal to 9.5 cm had a 93% sensitivity and a 90.5% specificity in the prediction of LBW. An MAC cutoff value of less than or equal to 9.5 cm was also the best of all variables in the prediction of early postnatal morbidity, and 85.2% sensitivity and 74.3% specificity were achieved. We conclude that in developing countries, where scales are not always available and the overburdened maternity wards cannot allow for medical surveillance of every infant, the MAC can be used in the estimation of birth weight. Moreover, an appropriately calculated cutoff value of MAC may serve as a reliable indicator of LBW and of infants at risk for early postnatal morbidity.