Ayumi Onoue

A Large Cohort Study Concerning Age-Dependent Impacts of Anthropometric Variables on Spirometric Parameters in Nonsmoking Healthy Adults

Backgrounds Although height (H) has been considered the principal anthropometric variable governing lung function, the age-dependent differences in its influences on determining spirometric parameters (SPs) have not been conclusively investigated. Moreover, there has been no study centered on age-dependent effects of other anthropometric variables, including body weight (BW) and body fat mass (BFM) on SPs. In addition, the age-dependent influences of these anthropometric variables are anticipated to differ quantitatively between male and female participants. Methods A total of 16,919 nonsmoking healthy Japanese adults (men: 6,116, women: 10,803) were partitioned into six groups stratified by gender and age at intervals of 20-years: young-, middle-, and advanced-age groups of either gender. Using a model in which a SP was described by a logarithmic additive function of age, H, BW, and BFM, we determined the partial regression coefficients of the respective anthropometric variables to predict the reference means of SPs, including FVC, FEV1, FEV1/FVC, PEF, FEF50, and FEF75, in the six groups. Results/Discussion Although the impact of H on FVC and FEV1 was relatively homogeneous irrespective of gender and age, its homogeneity faded for flow parameters, particularly in the female middle- and advanced-age groups, indicating that the age-dependent contribution of H to SPs was enhanced more in women. The impact of BW on SPs differed depending on age, and this effect was also more conspicuous for female participants. H and BW generally exerted positive effects on SPs, whereas BFM had negative effects. Opposite effects of BW and BFM were observed in the female middle-age group in particular. Conclusions The effects of anthropometric variables on spirometric parameters are highly age-dependent, particularly in women, leading to the conclusion that the assumption of age-independent, constant partial regression coefficients of anthropometric variables while predicting the reference mean of a certain spirometric parameter may result in substantial errors.

Novel regression equations predicting lung age from varied spirometric parameters

Although lung age calculated backward from regression formulas constructed for FEV(1) estimation is widely used, it possesses a couple of faults. We developed novel equations predicting lung age from varied spirometric parameters (spirometry-derived lung age (SDL-age)). Applying multiple regression analysis, equations predicting SDL-age were invented using data from 8015 never-smokers with normal spirometry (group I). Validation was made based on data from 6398 never-smokers with normal spirometry (group II). Equations were further applied for 446 subjects with airflow limitation. FEV(1), FEV(1)/FVC, FEF(50), and PEF were selected as explanatory variables for reference value of SDL-age. Normal limits of difference between SDL-age and chronological-age were ± 13.4 years in the male and ± 15.0 years in the female. Established equations predicted SDL-age of group II. SDL-age was older than chronological-age only in subjects with severe airflow limitation. Novel regression equations allowing prediction of reference value of SDL-age and normal limits of difference between SDL-age and chronological-age were elaborated in both genders.

Association between Airflow Limitation Severity and Arterial Stiffness as Determined by the Brachial-Ankle Pulse Wave Velocity: A Cross-Sectional Study

Objective Chronic obstructive pulmonary disease (COPD) is often associated with concomitant systemic manifestations and comorbidities, such as cardiovascular disease. There are limited data regarding airflow limitation (AL) and atherosclerosis in Japanese patients, and the potential association between AL and arterial stiffness has not yet been investigated in Japanese patients. Therefore, the purpose of this study was to investigate the association between AL severity and arterial stiffness using the brachial-ankle pulse wave velocity (baPWV). Methods This cross-sectional study included 1,356 subjects aged 40-79 years without clinical cardiovascular diseases who underwent a comprehensive health screening that included spirometry, the baPWV measurement, and blood sampling during medical check-ups in 2009 at the Japanese Red Cross Kumamoto Health Care Center. AL was defined in accordance with the Global Initiative for COPD criteria (forced expiratory volume in one second / forced vital capacity of < 0.7). A cut-off baPWV value of >1,400 cm/s was used for risk prediction and screening. Results The average baPWV (SD) results were 1,578.0 (317.9), 1,647.3 (374.4), and 1,747.3 (320.1) cm/s in the patients with a normal pulmonary function, mild AL, and moderate-to-severe AL, respectively (p< 0.001). Using logistic regression models adjusted for the age, body mass index, smoking status, hypersensitive C-reactive protein levels, hypertension, hyperglycemia, and dyslipidemia, an increased baPWV (>1,400 cm/s) was significantly associated with moderate-to-severe AL compared with a normal pulmonary function (odds ratio=2.76; 95% confidence intervals, 1.37-5.55; p=0.004). Conclusion Our results indicated an association between AL and increased arterial stiffness. Arterial stiffness may therefore worsen with an increase in the severity of AL.

Relationship of airflow limitation severity with work productivity reduction and sick leave in a Japanese working population.

Background The aim of this study was to reveal the association between airflow limitation (AL) severity and reduction with work productivity as well as use of sick leave among Japanese workers. Methods This cross-sectional study included 1,378 workers who underwent a lung function test during a health checkup at the Japanese Red Cross Kumamoto Health Care Center. AL was defined as forced expiratory volume in 1 second/forced vital capacity of <0.7. Workers completed a questionnaire on productivity loss at work and sick leave. The quality and quantity of productivity loss at work were measured on a ten-point scale indicating how much work was actually performed on the previous workday. Participants were asked how many days in the past 12 months they were unable to work because of health problems. Logistic regression analysis was used to assess the associations between AL severity and the quality and quantity of productivity loss at work as well as use of sick leave. Results Compared with workers without AL, workers with moderate-to-severe AL showed a significant productivity loss (quality: odds ratio [OR] =2.04, 95% confidence interval [CI]: 1.12–3.71, P=0.02 and quantity: OR =2.19, 95% CI: 1.20–4.00, P=0.011) and use of sick leave (OR =2.69, 95% CI: 1.33–5.44, P=0.006) after adjusting for sex, age, body mass index, smoking status, hypertension, hyperglycemia, dyslipidemia, sleep duration, work hours per day, and workplace smoking environment. Conclusion AL severity was significantly associated with work productivity loss and use of sick leave. Our findings suggested that early intervention in the subjects with AL at the workforce might be beneficial for promoting work ability.

Novel Regression Equations Incorporating Aging-specific Contributions of Various Explanatory Variables in Predicting Spirometric Parameters in Non-Obese, Japanese Adults

Aim: To develop the novel regression equations that predict spirometric parameters (SPs) in concert with aging-specific corrections for four explanatory variables, including age, height, body weight, and fat fraction of body mass. Subjects: A large cohort of nonsmoking, non-obese, healthy adults in the general population in Japan (males: 3,056, females: 6,783). Methods: Supposing that SP is described by an aging-dependent, logarithmic, additive function of age, height, body weight, and fat fraction of body mass, gender- and aging-specific regression equations predicting the forced vital capacity (FVC), forced expiratory volume after one second (FEV1), FEV1/FVC, peak expiratory flow rate (PEF), forced expiratory flow rate at 50% expiration of the FVC (FEF50), and forced expiratory flow rate at 75% expiration of the FVC (FEF75) were established. The partial regression coefficients of explanatory variables against a specific SP were decided by a step-wise, multiple-regression analysis with least-squares minimization. Results: Age and fact fraction of body mass exerted negative impacts, whereas height and body weight had positive impacts on various SPs in an aging-dependent and/or aging-independent manner. These aging-related contributions of explanatory variables were highly gender-specific. Body weight and fat fraction of body mass concurrently played an important role in prescribing the SP, particularly in females. Conclusions: The gender-specific, aging-related corrections of age, height, body weight, and fat fraction body mass are important for deciding various spirometric parameters. If the aging-dependent and/or aging-independent contributions of body weight and/or fat fraction of body mass are ignored, substantial errors emerge for the reference means and lower limits of normal of specific SPs