Associations between proximity to livestock farms, primary health care visits and self-reported symptoms
Dijk et al. BMC Family Practice
Associations between proximity to livestock farms, primary health care visits and self-reported symptoms
Christel E. van Dijk 0
Lidwien A. M. Smit 2
Mariette Hooiveld 0
Jan-Paul Zock 0
Inge M. Wouters 2
Dick J. J. Heederik 2
C. Joris Yzermans 0
0 NIVEL, Netherlands Institute for Health Services Research , Utrecht , The Netherlands
1 Centre for Research in Environmental Epidemiology (CREAL) , Barcelona , Spain
2 Utrecht University, Institute for Risk Assessment Sciences, Division Environmental Epidemiology , Utrecht , The Netherlands
3 CIBER Epidemiología y Salud Pública (CIBERESP) , Madrid, Madrid , Spain
4 Universitat Pompeu Fabra (UPF) , Barcelona , Spain
Background: Living in a neighbourhood with a high density of livestock farms has been associated with adverse respiratory health effects, but less is known about healthcare utilisation. This study aimed at investigating the associations between livestock exposure and primary health care visits and self-reported symptoms. In addition, we examined the potentially confounding effect of distance from home to general practice. Methods: Contact data between 2006 and 2009 were obtained from electronic medical records of 54,777 persons registered within 16 general practices in an area with a high density of livestock farms in the Netherlands. Data on self-reported symptoms were used from a cross-sectional sample of 531 patients in 2010. Livestock presence in a 500 m radius from home was computed using Geographic Information System data. Results: In general, livestock exposure was associated with fewer contacts and self-reported symptoms for respiratory and other conditions. The number of poultry within 500 m was positively associated with the number of contacts. A longer distance to general practice was associated with fewer contacts, but did not confound associations. Conclusions: People living close to livestock farms less often see their general practitioner and report symptoms.
Environmental exposure; Respiratory system; Delivery of health care; Primary health care; Livestock
Background
Living in a neighbourhood with a high density of
livestock farms has been associated with adverse respiratory
health effects [
1–3
]. Livestock farms are known to
contain several compounds, including microbial compounds
such as bacteria, endotoxins, fungi, viruses, pathogenic
infectious agents, and also particular matter (PM),
ammonia, hydrogen sulphide (H2S) and volatile organic
compounds [
4
]. Through ventilation and diffusion, these
compounds may emit to the environment. However,
information on exposure levels in the vicinity of livestock farms
in general is scarce [
4
]. Several studies showed a higher
prevalence of wheezing and difficulty in breathing, and
lower lung function with increased livestock exposures in
residents near farms [
1–3
]. However, the association
between livestock exposures and the prevalence of
respiratory diseases is inconclusive. One study found a lower
prevalence of asthma, COPD and allergic rhinitis, one
study a higher prevalence of asthma and two studies
found no difference in the prevalence of asthma or allergic
rhinitis with increased livestock exposures [
1, 3, 5, 6
]. The
association between exposure to livestock and healthcare
utilisation was not examined until now.
As areas with a high density of livestock farms are
located in rural areas with a lower geographical density of
general practices, access to healthcare might be
compromised compared to more urban areas as travel time to
healthcare providers is increased. Literature with regard to
travel time or distance to healthcare and healthcare
utilisation points towards decreased healthcare utilisation with
increased distance [
7
]. Thus, higher respiratory healthcare
utilisation due to respiratory health problems with
increased livestock exposure may be counterbalanced by
lower accessibility of healthcare. In other words, distance
to healthcare providers might be an important confounder
in the association between exposure to livestock exposures
and primary healthcare utilisation.
The objective of this study is to illuminate the
association between livestock exposure and healthcare
utilisation, in terms of contacts in general practice, using data
from electronic medical records (EMRs) of general
practices of residents living in an area in the Netherlands
with a high density of livestock farms. This study
addresses the following questions:
What is the association between livestock exposure
and (respiratory) contacts in general practice? Does
distance to general practice confound associations
between livestock exposure and (respiratory) contacts?
Lower healthcare utilisation could both indicate a
lower demand for healthcare and a lower accessibility of
healthcare. To be fully certain that possible differences
(after adjusting for distance to general practice)
represent differences in demand and not accessibility, we
additionally analyse (...truncated)