Dementia is a leading cause of disability and mortality worldwide. While the disorder is widely recognized, public awareness of modifiable risk and potentially protective factors remains limited. This is despite evidence that a substantial proportion of cases could be prevented or delayed by modifying personal risk factors. To date, the influence of sociodemographic factors on knowledge about dementia prevention has not been sufficiently examined, particularly in Germany, leaving a critical gap for targeted public health strategies.

To assess awareness of the preventability of dementia and to evaluate knowledge of risk and protective factors in the German population, with particular focus on the influence of age, sex, and education.

Online, cross-sectional survey study.

German population. A link to the survey was distributed nationwide via e-mail, flyers, and social media.

Adults aged ≥18 years without diagnosed cognitive impairment. A total of 2610 individuals completed the survey, of whom 2515 (mean age 52.5 years, range 18–95, 69.8% female) were included in the analysis.

Awareness of dementia, risk factors, and preventability was assessed using two dichotomous and three Likert-scale items. Knowledge of 23 evidence-based risk and protective factors (plus sham items) was measured with Likert-scale items. Composite knowledge scores were derived from these items, including separate subscores for medical and lifestyle-related risk factors. Preferred information dissemination sources were assessed using a multiple-choice item. Analyses included descriptive statistics and regression models with age, sex, and education as predictors.

While almost all respondents (98.2%) affirmed knowing what dementia is, only 73% affirmed awareness of risk-modifying factors, with substantial subgroup differences. Nearly 38% did not agree that dementia can be prevented, including a higher proportion of those aged ≥75 years (52%). Lifestyle factors, such as physical, mental, and social activity and diet, were most frequently recognized (>75%), whereas medical and environmental risks (e.g., cardiovascular disease, kidney disease, air pollution) were consistently underrecognized (<50%). Overall, younger age, female sex, and higher education were predictors of significantly higher knowledge scores, with education showing the strongest effect. Preferred information sources also differed systematically; lower-educated participants and men were more likely to rely on general practitioners, while higher-educated groups preferred digital resources and specialized organizations.

Compared with findings from previous German surveys, awareness of dementia preventability is higher in the present sample; however, knowledge about specific influencing factors—particularly medical—remains limited. As awareness, knowledge, and preferred information channels differ across age, sex, and education groups, educational efforts should be tailored accordingly.