Introduction: Swallowing impairment (SI) is an underdiagnosed dysfunction frequently seen as an expected condition of aging. However, SI can lead to health complications and considerable social impact.

Methods: The objective of this systematic review with meta-analysis was to evaluate the frequency and associated factors with SI in community-dwelling older persons. Searches were performed in 13 electronic databases including MEDLINE and EMBASE (from inception to September 18, 2021). Data extraction and methodological quality assessment of included studies were performed by two independent reviewers. Meta-analysis of proportions with 95% confidence interval (CI) and prediction interval (PI) was used to pool estimates. Subgroup analysis by Country and Assessment Method was performed. General meta-analysis was used to pool measures of association between potential risk factors and SI occurrence (odds ratio [OR] or prevalence ratio [PR]).

Results: The worldwide estimated frequency of SI in community-dwelling older persons was 20.35% (95%CI 16.61-24.68%, 95%PI 4.79-56.45, I(2) 99%, n = 33,291). This estimation varied across assessment methods and by country. The main factors associated with SI were a dry mouth (OR 8.1, 95%CI 4.9-13.4), oral diadochokinesis (OR 5.3, 95%CI 1.0-27.3), ≥ 80 years old (OR 4.9, 95%CI 2.6-9.2), genetic factor (SNPrs17601696) (OR 4.8, 95%CI 2.7-8.3), and partial dependence (OR 4.3, 95%CI 2.0-9.3). And the main factors associated with SI estimated by PR were dry mouth sensation (PR 4.1, 95%CI 2.6-6.5), oral sensorimotor alteration (PR 2.6, 95%CI 1.4-4.9), osteoporosis (PR 2.51, 95%CI 1.2-5.3), and heart diseases (PR 2.31, 95%CI 1.1-5.0).

Conclusion: One in five older adults worldwide are expected to experience SI and factors associated with this underdiagnosed dysfunction included biological and physiological changes related to aging, physical and psychological conditions, and poor oral health. Early assessment is paramount for the prevention of future clinical complications and should be a high priority in health care practices.