Investigating the association between influenza vaccination and reduced stroke risk

Influence of sociodemographic inequalities and chronic conditions on influenza vaccination coverage in Italy: results from a survey in the general population

OBJECTIVE

To assess inequalities in vaccination against seasonal influenza determined by sociodemographic and health-related factors.

STUDY DESIGN

A cross-sectional study was conducted using data from 128,040 subjects aged 1-89 years who participated the national survey 'Health Conditions and Health Care Services Use', conducted by the Italian National Centre of Statistics in 2005.

METHODS

This analysis included people aged ≥65 years, and individuals of any age with chronic medical conditions. The outcome variable was vaccination or non-vaccination against influenza in the last 12 months, and the explanatory variables were gender, age, smoking habit, educational level, macro-region of residence, chronic medical conditions, occupational status, marital status, self-assessed health status and self-assessed household income. Univariate and multivariate analyses were conducted using Chi-squared test and multiple logistic regression models. For the latter analysis, results are presented as odds ratios (OR) and 95% confidence intervals (CI) of being vaccination against influenza in the last 12 months.

RESULTS

Approximately 20% of subjects had been vaccinated against influenza in the previous 12 months. Older age (≥65 years), current smoker, poor health status, poor self-assessed household income and the presence of at least one chronic condition were positively associated with influenza vaccination (P < 0.05). The lowest ORs for influenza vaccination were found in current smokers (adjusted OR vs non-smokers 0.699, 95% CI 0.697-0.701), young adults (adjusted OR 15-24 years vs ≥65 years 0.073, 95% CI 0.072-0.073; adjusted OR 25-34 years vs ≥65 years 0.097, 95% CI 0.096-0.097), subjects with a lower secondary education or professional school (adjusted OR vs primary education 0.910, 95% CI 0.908-0.913), subjects living in the Islands (adjusted OR vs North-eastern Italy 0.760, 95% CI 0.757-0.763), and unemployed subjects (adjusted OR vs employed 0.867; 95% CI 0.859-0.875). The ORs for vaccination were lower for some chronic conditions (e.g. allergies, cirrhosis) than others (e.g. cancer, stroke, bronchitis). Younger age groups, including children aged 0-14 years, had lower ORs for vaccination.

CONCLUSIONS

Socio-economic factors, such as gender, age, educational level, occupational status and macro-region of residence, affect influenza vaccination coverage rates in the Italian general population. In addition, some chronic medical conditions are an obstacle for vaccination.