Improvements in PM10 exposure and reduced rates of respiratory symptoms in a cohort of Swiss adults (SAPALDIA).
BACKGROUND
Reductions in mortality following improvements in air quality were documented by several studies, and our group found, in an earlier analysis, that decreasing particulate levels attenuate lung function decline in adults.


OBJECTIVE
We investigated whether decreases in particulates with an aerodynamic diameter of less than 10 microm (PM10) were associated with lower rates of reporting respiratory symptoms (i.e., decreased morbidity) on follow-up.


METHODS
The present analysis includes 7,019 subjects who underwent detailed baseline examinations in 1991 and a follow-up interview in 2002. Each subject was assigned model-based estimates of average PM10 during the 12 months preceding each health assessment and the difference was used as the exposure variable of interest (DeltaPM10). Analyses were stratified by symptom status at baseline and associations between DeltaPM10 and change in symptom status during follow-up were adjusted for important baseline characteristics, smoking status at follow-up, and season. We then estimated adjusted odds ratios for symptoms at follow-up and numbers of symptomatic cases prevented due to the observed reductions in PM10.


RESULTS
Residential exposure to PM10 was lower in 2002 than in 1991 (mean decline 6.2 microg/m3; SD = 3.9 microg/m3). Estimated benefits (per 10,000 persons) attributable to the observed changes in PM10-levels were: 259 (95% confidence interval [CI]: 102-416) fewer subjects with regular cough, 179 (95% CI, 30-328) fewer subjects with chronic cough or phlegm and 137 (95% CI, 9-266) fewer subjects with wheezing and breathlessness.


CONCLUSIONS
Reductions in particle levels in Switzerland over the 11-year follow-up period had a beneficial effect on respiratory symptoms among adults.
Schindler
Christian
C
Institute of Social and Preventive Medicine, University of Basel, Steinengraben 49, CH 4051 Basel, Switzerland. christian.schindler@unibas.ch
Keidel
Dirk
D
Gerbase
Margaret W
MW
Zemp
Elisabeth
E
Bettschart
Robert
R
Brändli
Otto
O
Brutsche
Martin H
MH
Burdet
Luc
L
Karrer
Werner
W
Knöpfli
Bruno
B
Pons
Marco
M
Rapp
Regula
R
Bayer-Oglesby
Lucy
L
Künzli
Nino
N
Schwartz
Joel
J
Liu
Lee-Jane S
LJ
Ackermann-Liebrich
Ursula
U
Rochat
Thierry
T
D000328:Adult; D003371:Cough / Q000453:epidemiology* / Q000209:etiology; D004417:Dyspnea / Q000453:epidemiology* / Q000209:etiology; D052918:Environmental Restoration and Remediation; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D015994:Incidence; D019570:Inhalation Exposure / Q000009:adverse effects* / Q000032:analysis; D008297:Male; D008875:Middle Aged; D016017:Odds Ratio; D052638:Particulate Matter / Q000009:adverse effects* / Q000032:analysis; D012135:Respiratory Sounds / Q000209:etiology; D013557:Switzerland / Q000453:epidemiology
D052638:Particulate Matter