Risk factors for allergy: Evidence from cross sectional analysis of a UK
primary care database.
Background: As the global prevalence of allergy increases, it is clear
that more individuals are presenting with complex and multiple
allergies. The impact of various demographic and clinical risk factors
on developing allergies has not been explored at a population level.
Objectives: To ascertain if age, gender, ethnicity, UK geographical
region of residence and being diagnosed with another allergy affect the
risk of having allergies. Methods: A retrospective analysis was
performed using cross-sectional data for the year 2018 extracted from
the from the health improvement network (THIN) database. THIN is a live
primary care database which holds entries about 6% of the UK
population. A logistic regression analysis was carried out using
demographic data and allergy diagnoses as independent variables.
Results: Of the 3.03 million records analysed, 49.8% were male and
19.7% were children (aged < 18 yrs). There were gender,
ethnicity and region-based differences in the prevalence of GP diagnosed
allergic diseases in the UK. The odds of developing anaphylaxis are
highest in individuals with food allergy [OR: 54.57 (95%CI:
45.65-65.22); p<0.001 for children and OR:18.05 (95%
CI:16.79-19.41); p<0.001 for adults respectively].
Individuals with any diagnosed allergy had significantly higher odds of
being diagnosed with others. Conclusions: Having an allergy
significantly increases the odds of being diagnosed with others. There
are age, gender, ethnicity and region based differences in the
prevalence of allergies. These data suggest that the number of
individuals with multiple allergies is increasing and that the needs of
increasingly cosmopolitan populations should be taken into account when
planning allergy services.