Effects of indoor molds and smoking on lung function levels among adults with newly diagnosed asthma and healthy adults

Abstract Indoor mold exposure and tobacco smoking are common worldwide. Only a few previous studies have addressed the potential effects of the exposures of these on lung function among adults who have asthma. In Study I and Study II, we investigated the potential effects of indoor dampness and mold exposures on lung function among adults with newly diagnosed asthma and non-asthmatic adults. In Study III, we assessed the potential effects of smoking on lung functions reflecting both large and small airways among adults with newly onset asthma. All studies are based on the Finnish Environment and Asthma Study (FEAS) that included 521 working-aged adults with incident asthma and 932 non-asthmatic adults. They answered a questionnaire on exposures and performed spirometry. A multiple linear regression model was applied to study the relationship between exposures and lung function levels. Among adults who had asthma, exposure to mold odor at home or at work or both was related to a significantly reduced FEV1 level (−240 ml, 95% CI −480 to −3), where the effect was detected mainly in men. Among the whole non-asthma population, exposure to mold odor had some adverse effects on spirometry levels. When stratified by gender, women had on average a 510 ml reduced FEV1 level (95% CI −1040 to 30) and an 820 ml reduced FVC level (95% CI −1440 to −20) in relation to mold odor exposure at home. The FEV1 level was reduced on average by 208 ml in relation to regular smoking (95% CI −355 to −61) and on average by 245 ml in relation to former smoking (95% CI −485 to −4) among those who had quit less than a year ago. Forced expiratory flow (FEF) rates (l/s) were also significantly reduced among regular smokers (FEF25–75%: −0.372, 95% CI −0.607 to −0.137; FEF50%: −0.476, 95% CI −0.750 to −0.202). An exposure–response pattern was detected in relation to both the daily smoking rate and lifetime cumulative smoking when investigating their effects on both large and small airways. This thesis provides new evidence that indoor exposure to mold odor reduces lung function levels among both working-aged adults with new asthma and those who are healthy, and that among working-aged adults who have asthma, regular smoking and former smoking reduce lung function levels with a dose–response pattern in both large and small airways.Tiivistelmä Altistuminen sisäilman homeille ja tupakointi ovat yleisiä maailmanlaajuisesti. Vain muutama tutkimus on arvioinut näiden altisteiden vaikutuksia keuhkojen toimintaan aikuisilla. Tutkimuksissa I ja II arvioimme sisäilman kosteus- ja homevaurioiden mahdollista vaikutusta keuhkojen toimintaan vastikään astmaan sairastuneilla ja terveillä aikuisilla. Tutkimuksessa III arvioimme tupakoinnin mahdollista vaikutusta keuhkojen toimintaan, sekä isojen että pienten ilmateiden osalta, vastikään astmaan sairastuneilla aikuisilla. Kaikki tämän väitöskirjan tutkimukset perustuvat väestöpohjaiseen tapaus-verrokkitutkimukseen (Finnish Environment and Asthma Study). Se koostui 521 työikäisestä aikuisesta, joilla on hiljattain diagnosoitu astma ja 932 terveestä aikuisesta. Tutkittavien altistuminen arvioitiin kyselytutkimuksella ja he suorittivat spirometrian. Usean muuttujan lineaarista regressioanalyysia käytettiin altistumisen ja spirometria-arvojen välisen yhteyden tutkimiseen. Aikuisilla astmaa sairastavilla homeen hajulle altistuminen töissä, kotona tai molemmissa oli yhteydessä merkittävästi alentuneeseen FEV1-tasoon (−240 ml, 95 % LV −480…−3). Tämä yhteys havaittiin lähinnä miehillä. Terveiden ryhmässä merkittävin vaikutus havaittiin naisilla, jotka altistuivat homeen hajulle kotona. Heillä keskimääräinen FEV1-taso oli 510 ml (95 % LV −1040–30) ja FVC-taso oli 820 ml (95 % LV −1440…−20) matalampi kuin altistumattomilla. Muut home- ja kosteusvaurion merkit eivät olleet selkeästi yhteydessä keuhkojen toimintaan. Säännöllisesti tupakoivilla FEV1-taso oli keskimäärin 208 ml matalampi (95 % LV −355…−61) ja alle vuosi sitten tupakoinnin lopettaneilla keskimäärin 245 ml (95 % LV −485…−4) matalampi tupakoimattomiin verrattuna. FEF-arvot (l/s) olivat myös merkittävästi alentuneet säännöllisesti tupakoivilla (FEF25–75 %: −0.372, 95 % LV −0.607…−0.137; FEF50 %: −0.476, 95 % LV -0.750…−0.202). Annos-vastesuhde havaittiin päivittäisen tupakoinnin määrän ja elinaikaisen kumulatiivisen altistumisen suhteen, kun tutkittiin tupakoinnin vaikutusta suuriin ja pieniin ilmateihin. Tämä väitöskirja tuo uutta näyttöä siitä, että sisäilman homeen hajulle altistumien heikentää keuhkojen toimintaa astmaa sairastavilla ja terveillä aikuisilla. Lisäksi astmaa sairastavilla aikuisilla säännöllinen tupakointi ja aiempi tupakointi heikentävät sekä isojen että pienten ilmateiden toimintaa

Smoking and lung function among adults with newly onset asthma

Introduction Smoking increases the risk of asthma and reduces lung function among subjects with and without asthma. We assessed the effects of smoking on lung function reflecting both central and small airways among adults with newly onset asthma. Methods In a population-based study, 521 (response rate 86%) working-aged adults with clinically defined newly diagnosed asthma answered a questionnaire on personal smoking and other factors potentially influencing lung function, and performed spirometry. We applied multiple linear regression analysis to estimate the relations between smoking and lung function adjusting for confounding. Results Among asthmatics, FEV1 level was reduced significantly, on average 208 mL, related to regular smoking (adjusted effect estimate -0.208, 95% CI -0.355 to -0.061) and 245 mL in relation to former smoking, that is, among those who quit less than a year ago (-0.245, 95% CI -0.485 to -0.004). In contrast, FEV1 was not significantly related to occasional smoking or former smoking among those who quit over a year ago. Forced expiratory flow (FEF) levels (L/s) were also significantly reduced among regular smokers (FEF25-75%: -0.372, 95% CI -0.607 to -0.137; FEF50%: -0.476, 95% CI -0.750 to -0.202). An exposure-response pattern related to both daily smoking rate and lifetime cumulative smoking was seen both among men and women. Conclusions This study provides new evidence that among working-aged adults with new asthma, regular smoking and former smoking reduce lung function levels with a dose-response pattern. The lung function parameters applied as outcomes reflect both larger and smaller airways.Peer reviewe

Regular exercise improves asthma control in adults:a randomized controlled trial

Abstract We conducted a randomized controlled trial to test the hypothesis that a 24-week exercise intervention improves asthma control in adults. Adults with mild or moderate asthma were randomly assigned to either the exercise intervention group (IG) or the reference group (RG). Participants in IG received an individualized exercising program, including aerobic exercise at least three times a week for ≥30 minutes, muscle training, and stretching. The primary outcome was asthma control, measured by Asthma Control Test (ACT), asthma-related symptoms, and peak expiratory flow (PEF) variability. We estimated the risk (i.e. probability) of improvement in asthma control and the risk difference (RD) between IG and RG. Of 131 subjects (67 IG/64 RG) entered, 105 subjects (51/54) completed the trial (80%), and 89 (44/45) were analysed (68%). The ACT became better among 26 (62%) participants in IG and among 17 (39%) participants in RG. The effect of intervention on improving asthma control was 23% (RD = 0.23, 95% CI 0.027–0.438; P = 0.0320). The intervention also reduced shortness of breath by 30.1% (RD = 0.301, 95% CI 0.109–0.492; P = 0.003). The change in PEF variability was similar in both groups. Regular exercise improves asthma control measured by the ACT, while has little effect on PEF variability