Loneliness is a significant health issue affecting a large portion of the population, with increased risks for mental health, suicidal ideation, health behavior, and healthcare utilization. A study using data from the Gutenberg Health Study (GHS) found that 10.5% of participants reported some degree of loneliness, with 4.9% experiencing slight, 3.9% moderate, and 1.7% severe loneliness. Loneliness was more common in women, those without a partner, and those living alone. It declined with age and was associated with depression, generalized anxiety, and suicidal ideation. Lonely individuals were more likely to smoke and visit physicians more frequently. The study highlights the importance of addressing loneliness as a public health concern, particularly in middle-aged and older adults. Loneliness was linked to poorer mental health outcomes and increased healthcare use. The findings suggest that loneliness should be considered a key health variable, especially in large-scale surveys. The study's strengths include a large sample size and standardized self-report measures, but its cross-sectional design limits causal conclusions. Future research is needed to validate the single-item loneliness measure and explore its impact on mental health in younger populations.Loneliness is a significant health issue affecting a large portion of the population, with increased risks for mental health, suicidal ideation, health behavior, and healthcare utilization. A study using data from the Gutenberg Health Study (GHS) found that 10.5% of participants reported some degree of loneliness, with 4.9% experiencing slight, 3.9% moderate, and 1.7% severe loneliness. Loneliness was more common in women, those without a partner, and those living alone. It declined with age and was associated with depression, generalized anxiety, and suicidal ideation. Lonely individuals were more likely to smoke and visit physicians more frequently. The study highlights the importance of addressing loneliness as a public health concern, particularly in middle-aged and older adults. Loneliness was linked to poorer mental health outcomes and increased healthcare use. The findings suggest that loneliness should be considered a key health variable, especially in large-scale surveys. The study's strengths include a large sample size and standardized self-report measures, but its cross-sectional design limits causal conclusions. Future research is needed to validate the single-item loneliness measure and explore its impact on mental health in younger populations.