The effect of occupational farming on lung function development in young adults: a 15-year follow-up study.
OBJECTIVE
Longitudinal studies on the effect of farming on lung function in young participants are few. Our objective was to explore if exposure to farming impaired lung function in young adults.


METHODS
We studied 1964 farming students and 407 controls in 1992/2004, and carried out follow-up in 2007/2008. Spirometry, skin prick test and bronchial hyper-responsiveness (BHR) were assessed, height and weight measured, and questionnaires covering health and occupation were collected. Cumulative dust and endotoxin exposures were estimated from modelled personal dust measurements. Lung function effect was expressed as change in z-score during follow-up using the Global Lung Initiative 2012 project prediction equations. Longitudinal data were available for 1134 young participants ≤25 years at baseline.


RESULTS
We found no differences in lung function Δz-scores between farmers and controls, however, adjusted multivariable linear regression showed a negative effect among current farmers on ΔzFEV1 (forced expiratory volume in 1 s; -0.12, p=0.006) and ΔzFEV1/FVC (forced vital capacity; -0.15, p=0.009) compared to ex-farmers. An interaction was found between sex and farming, showing that current farming suppresses ΔzFEV1 and ΔzFVC more among females. Smoking in farmers had a deleterious effect on ΔzFEV1, which was not seen in controls, though no significant interaction was found. Farm upbringing protected against impairment of lung function, and BHR at baseline had a deleterious effect on ΔzFEV1 only in those not raised on a farm.


CONCLUSIONS
We conclude that being a current farmer is associated with a negative effect on lung function, when compared to ex-farmers, with females being more susceptible. Being raised on a farm protects against the adverse effect of BHR on change in lung function.
Department of Public Health, Section of Environment Occupation and Health, Danish Ramazzini Centre, University of Aarhus, Aarhus C, Denmark.
Anneli C S
AC
Bolund
Institute of Occupational and Environmental Medicine, University of Birmingham, Birmingham, West Midlands, UK.
Martin R
MR
Miller
Department of Public Health, Section of Environment Occupation and Health, Danish Ramazzini Centre, University of Aarhus, Aarhus C, Denmark.
Ioannis
http://orcid.org/0000-0001-7708-3017
I
Basinas
Department of Public Health, Section of Environment Occupation and Health, Danish Ramazzini Centre, University of Aarhus, Aarhus C, Denmark.
Grethe
G
Elholm
Department of Occupational Medicine, Danish Ramazzini Centre, Aalborg University Hospital, Aalborg, Denmark.
Øyvind
Ø
Omland
Department of Public Health, Section of Environment Occupation and Health, Danish Ramazzini Centre, University of Aarhus, Aarhus C, Denmark.
Torben
T
Sigsgaard
Department of Public Health, Section of Environment Occupation and Health, Danish Ramazzini Centre, University of Aarhus, Aarhus C, Denmark.
Vivi
V
Schlünssen
D000328:Adult; D000367:Age Factors; D000382:Agricultural Workers' Diseases / Q000175:diagnosis* / Q000453:epidemiology; D000383:Agriculture / Q000193:education*; D016022:Case-Control Studies; D003718:Denmark; D004391:Dust; D005260:Female; D005541:Forced Expiratory Volume / Q000502:physiology; D006801:Humans; D015994:Incidence; D008137:Longitudinal Studies; D008297:Male; D016273:Occupational Exposure / Q000009:adverse effects*; D016272:Occupational Health; D012016:Reference Values; D012129:Respiratory Function Tests; D018570:Risk Assessment; D012737:Sex Factors; D013147:Spirometry; D013334:Students; D055815:Young Adult
D004391:Dust