Alcohol, smoking, and physical activity related to respiratory infections in elderly people.

OBJECTIVE: Elderly people show an increased risk of acute respiratory infections and their complications. This increased susceptibility may be the result of immunosenescence. If lifestyle factors could influence the risk of the infections, this could result in great public health relevance. We investigated the relation between alcohol consumption, smoking, and physical activity with acute respiratory infections. DESIGN: Prospective observational analysis. SETTING: The study took place between September 1998 - June 2000, in the Wageningen area of The Netherlands. PARTICIPANTS: In total 652 relatively healthy elderly people participated. Participants were noninstitutionalized and 60 years and older. MEASUREMENTS: The lifestyle factors were assessed at baseline by means of standardized and validated questionnaires in the participants. Self-reported respiratory infections were assessed from 1998-2000 by nurse telephone contact, and home visits, and were evaluated by microbiological tests in a subset. RESULTS: We detected 1024 acute respiratory infections among 443 participants, the overall incidence rate (IR) was 1.6 infections per person per year. IR ratio (95% confidence interval) of the infections was 1.31 (1.01, 1.70) for occasional (superior 0 glasses/day < 1), 1.22 (0.92, 1.64) for light (1 < glasses/day < 3 (men) and 1< glasses/day < 2 (women)), and 1.33 (1.04, 1.83) at moderate/heavy (superior 3 (men) or superior 2 (women) glasses/day) alcohol consumption after adjustment for age and sex. Alcohol intake was not related to illness severity. Smoking and physical activity were not related to the incidence and severity of the infections. All results remained unaltered after adjustment for lifestyle factors and for other potential risk factors for respiratory infections. CONCLUSION: Our findings suggest that only alcohol intake may be unfavorably associated with the frequency of acute respiratory infections in apparently healthy elderly people. Until our results are confirmed in trials, it is not warranted to recommend elderly people to change their habits of life, such as alcohol consumption, smoking and physical activity in order to reduce the risk of acute respiratory infections.

Facilitatory beta2-adrenoceptors on cholinergic and adrenergic nerve endings of the guinea pig trachea.

Using electrical field stimulation of epithelium-denuded intact guinea pig tracheal tube preparations, we studied the presence and role of prejunctional beta2-adrenoceptors by measuring evoked endogenous acetylcholine (ACh) and norepinephrine (NE) release directly. Analysis of ACh and NE was through two HPLC systems with electrochemical detection. Electrical field stimulation (150 mA, 0.8 ms, 16 Hz, 5 min, biphasic pulses) released 29.1 +/- 2.5 pmol ACh/g tissue and 70.2 +/- 6.2 pmol NE/g tissue. Preincubation for 15 min with the selective beta2-adrenoceptor agonist fenoterol (1 microM) increased both ACh and NE overflow to 178 +/- 28 (P < 0.01) and 165 +/- 12% (P < 0.01), respectively, of control values, increases that were abolished completely by the selective beta2-adrenoceptor antagonist ICI-118551 (1 microM). Further experiments with increasing fenoterol concentrations (0.1-100 microM) and different preincubation periods (1, 5, and 15 min) showed a strong and concentration-dependent facilitation of NE release, with maximum response levels decreasing (from nearly 5-fold to only 2.5-fold of control value) with increasing agonist contact time. In contrast, sensitivity of facilitatory beta2-adrenoceptors on cholinergic nerves to fenoterol gradually increased when the incubation period was prolonged; in addition, a bell-shaped concentration-response relationship was found at 15 min of preincubation. Fenoterol concentration-response relationships (15-min agonist preincubation) in the presence of atropine and yohimbine (1 microM each) were similar in the case of NE release, but in the case of ACh release, the bell shape was lost. The results indicate a differential capacity and response time profile of facilitatory prejunctional beta2-adrenoceptors on adrenergic and cholinergic nerve terminals in the guinea pig trachea and suggest that the receptors on adrenergic nerves are more susceptible to desensitization.