Do psychological factors predict occurrence of influenza-like symptoms in vaccinated elderly residents of a sheltered home?

OBJECTIVES

A previously shown relation between psychological factors and the occurrence of flu has not been tested in elderly people, who are at the greatest risk of mortality from flu complications. This study examined whether psychological factors predict the occurrence of influenza-like symptoms (ILS) in elderly residents.

DESIGN

A prospective correlation design was used.

METHOD: Our sample included 70 elderly residents of a sheltered home (mean age 83.0 years) who were vaccinated against influenza and assessed for background, biomedical factors (e.g. number of illnesses) and psychological factors (e.g. hostility, depression, life-events, and social support). The occurrence of ILS during 2 subsequent winter months was evaluated by a nurse blind to patients' psychological data, according to explicit valid criteria and physicians' notes.

RESULTS

Seventeen patients (24.3%) developed ILS. Number of medications, little physical activity, hostility, depression, and little social support significantly predicted ILS. In a multivariate analysis, only number of drugs (relative risk, RR: 1.54; 95% confidence interval, CI: 1.06-2.22) and hostility (RR = 1.18; 95% CI: 1.00-1.38) significantly and independently predicted occurrence of ILS.

CONCLUSIONS

Psychological factors (particularly hostility) predict occurrence of ILS in an elderly sample. Possible behavioural and immunological mechanisms linking hostility to development of ILS are discussed. These findings add to the literature on psychological factors and flu, and may have implications for the prediction and prevention of flu in elderly people.