Yewande Odeyemi

Does fractional exhaled nitric oxide vary by foreign-born status and years of US residence?

Silverberg et al1 report that asthma prevalence is higher in US-born than in foreign-born adults regardless of region of birth. To extend the findings of Silverberg et al, we present previous unpublished data from the National Health and Nutrition Examination Survey (NHANES). Asthma and chronic obstructive pulmonary disease (COPD) are important causes of mortality and morbidity in adults.2,3 Inflammation of airways is an important mechanism leading to airway obstruction in these common conditions.4 In atopic asthma, inducible nitric oxide synthase is up-regulated in respiratory epithelium and produces increased nitric oxide concentrations in exhaled air.5 Fractional exhaled nitric oxide (FeNO) has gained favor in identifying and monitoring eosinophilic airway inflammation in patients with asthma or COPD being considered for inhaled corticosteroid therapy.6 Little information is available on region of birth and FeNO5; therefore, we estimated the association between nativity and years lived in the United States and FeNO using data from NHANES.7,8 FeNO was measured using the Aerocrine NIOXMINO, a portable, hand-held nitric oxide analyzer (Aerocrine AB, Solna, Sweden). This analysis uses the mean of 2 reproducible measurements.7,8 In 2007e2012, NHANES interviewed 30,442 participants, of whom 29,353 underwent examination; of those, 17,970 were 18 years or older, and 17,885 had data on asthma history and nativity. Prevalence of current diagnosis of asthma was 8.4% in US-born and 5.0% in foreign-born persons (P < .001). Among Hispanics, 7.1% of US-born and 4.1% of foreign-born people had current asthma diagnoses (P< .001). Among non-Hispanics, 8.5% of US-born and 5.9% of foreign-born people had current asthma diagnoses (P 1⁄4 .01). In logistic regression, the relative odds of asthma in foreign-born people was 0.65 (95% CI, 0.52e0.81; P < .001) after controlling for age, sex, Hispanic ethnicity, and black race. Therewas no significant interaction of foreign-born status with Hispanic ethnicity (P 1⁄4 .53). Among the foreign-born people, years lived in the United States was positively associated with asthma prevalence but was not statistically significant (b 1⁄4 1.14, P 1⁄4 .08). Among the subgroup of 14,229 adults with FeNO validly measured, geometric mean FeNO was 12.8 ppb for US-born and 14.7 ppb for 3,568 foreign-born adults. In linear regression, foreign nativity was significantly associated with lnFeNO after controlling for age, sex, Hispanic ethnicity, and black race (b1⁄40.13, P< .001) and remained significant after adding asthma history, hay fever history, and smoking to the model (b1⁄40.09, P < .001) (Table 1). Years lived in the United States were not significantly, positively related to lnFeNO (b1⁄40.011, P 1⁄4 .26) in the foreign-born people after controlling for age, sex, Hispanic ethnicity, black race, asthma history, hay fever history, and smoking. Possible explanations for asthma prevalence and FeNO appearing to go in opposite directions could be the underreporting of asthma in foreign-born people due to less access to care or to greater prevalence of eosinophilic airway inflammation vs other airway inflammation in foreign-born people not adequately controlled for using asthma history. Although the mean FeNO difference by nativity may be relatively small, describing such differences may suggest the above and other hypotheses for further study of asthmamechanisms. In conclusion, we confirm a lower prevalence of asthma in foreign-born people and a higher FeNO in foreign-born people independent of asthma history.

Effect modification by race–ethnicity of environmental tobacco smoke exposure on airway inflammation in US children

BACKGROUND Asthma mortality and morbidity are higher in black than in white children. Fractional exhaled nitric oxide (FeNO) is a noninvasive biomarker of eosinophilic airway inflammation. Identification of differences in the effect of environmental tobacco smoke (ETS) on airway inflammation by race and ethnicity from a large sample is needed. OBJECTIVE To estimate a racial difference in association with ETS and FeNO. METHODS Data from the 2007 to 2012 National Health and Nutrition Examination Survey were analyzed to compare associations of ETS and FeNO levels in US black and other children. No ETS exposure was defined as a serum cotinine level lower than 0.05 ng/mL and ETS exposure was defined as a serum cotinine level of at least 0.05 ng/mL. FeNO was measured using a device that relies on an electrochemical sensor. Analyses took the complex survey design into account. RESULTS The analytic sample was formed by 5,473 participants (6-11 years old, n = 2,385; 12-19 years old, n = 3,088) with complete data on demographics, serum cotinine levels, and 2 reproducible FeNO measurements. In weighted linear regression analyses at 6 to 11 years, the interaction term for ETS and black race was not significant (P = .15). At 12 to 19 years, the interaction term was significant (P = .03) in an analysis of all racial groups. In race-specific models, the coefficient for ETS exposure in blacks was -0.033 and that in others was -0.175, ie, ETS exposure was associated with a greater decrease in FeNO in non-blacks than in blacks. CONCLUSION There was no evidence at 6 to 11 years of age for an effect modification by race of the association between ETS and FeNO. At 12 to 19 years, the data suggested an effect modification.

Airflow Obstruction, Cognitive Function and Mortality in a US National Cohort: NHANES-III

To test the hypothesis that cognitive impairment increases mortality independent of airflow obstruction.

Screen Hours and Sleep Symptoms: The US National Health and Nutrition Examination Survey

Few studies have examined the relationship between television viewing, computer use, and sleep symptoms. We hypothesized that television and computer time was associated with sleep symptoms. Screen hours were the sum of daily TV hours and computer hours. A total of 4342 participants 20 years and older had data on screen hours. After adjusting for confounders, 4 or more screen hours were significantly associated with increased odds of reporting long sleep latency, nighttime awakening, high sleep hours, and snoring (P < .05). These findings suggest that increased screen/TV time is an important risk factor for sleep symptoms.

CHRONIC OBSTRUCTIVE PULMONARY DISEASE, COGNITIVE FUNCTION AND MORTALITY IN A U.S. NATIONAL COHORT: NHANES-III

Background: Chronic Obstructive Pulmonary Disease (COPD) is a common respiratory disease among elderly with its prognosis greatly determined by the presence of comorbidities including cognitive impairment. We hypothesized that baseline airway obstruction and cognitive impairment are independent predictors of survival in persons aged 60 years and over, and further that there is no positive interaction between these risk factors. Methods:We utilized the Third National Health and Nutrition Examination Survey (NHANES III), from 1988-1994 with mortality follow-up data through December 31, 2011. The ratio of the forced expiratory volume in the first second (FEV1) to the forced vital capacity (FVC) <0.7 was used to define airway obstruction. Cognitive function was assessed using a short index of cognitive function (SICF). SICF score <12 (range 0-17) indicated impairment in cognitive function. The number interviewed was 33,994 and 5,302 of these were aged 60 years. Of these 4,488 had mortality follow-up data, reliable spirometry data and no missing data. Results: 1930 (43%) were men and 2,558 (57%) were women. SICF <12 occurred in 2,761. 2152 had neither FEV1/FVC<0.7 nor SICF<12, 1131 had FEV1/FVC<0.7 only, 758 had SICF <12 only and 447 had both FEV1/FVC<0.7 and SICF<12. Over the follow-up period (min1⁄40, median1⁄4 200 months, maximum1⁄4 276 months) there were a total 3,335 deaths in the analysis sample. There were 1413 deaths among those with neither SICF <12 nor FEV1/FVC < 0.7, 902 with FEV1/FVC < 0.7 only, 615 with SICF <12 only and 405 with both SICF <12 and FEV1/FVC < 70%. Weighted Cox proportional hazards regression revealed increasing hazard ratio in persons with FEV1/FVC <0.7, SICF <12, and both FEV1/ FVC <0.7and SICF <12 respectively compared with persons with neither (reference group). After adjusting for multiple confounders, adjusted hazards ratios (95%CI) were 1.39(1.25-1.56)), 1.33 (1.15-1.53), 1.55(1.18-2.04), respectively. Further analysis assessing for interaction between FEV1/FVC ratio and SICF revealed a negative interaction (p 1⁄40.006) after adjusting for multiple confounders. Conclusions:Elderly persons with airway obstruction or cognitive impairment or both had increased all-cause mortality over the follow-up period when compared to those having neither. A negative interaction was significant. Further prospective studies are needed to replicate these findings.