Effects of vitamin D supplementation on depression in adult women: a systematic review of randomized controlled trials.

As the population ages at an accelerating pace, the prevalence of type 2 diabetes among older adults has been rising year by year, becoming a major global public health challenge (). According to statistics from the International Diabetes Federation, the number of adults aged 20–79 years with diabetes worldwide reached 589 million in 2024 and is projected to rise to 853 million by 2050 (). The diabetes epidemic in China is particularly severe. Studies show that the number of people with diabetes aged 20 years and older in China has reached 233 million, with the age-standardized prevalence rising from 7.53% in 2005 to 13.67%, and projected to reach 29.10% by 2025 (). Among these, the prevalence of diabetes among older adults is particularly striking. The population aged 60 years and older has exceeded 310 million, with approximately 78.9 million older adults living with diabetes, about 95% of whom have type 2 diabetes (). As physical function declines and social roles shift, older adults with type 2 diabetes experience corresponding changes in their activities of daily living and social participation, making them prone to insufficient social engagement (, ). Therefore, older adults with type 2 diabetes must not only focus on physiological blood glucose control but also pay close attention to the complex interplay between this control and the maintenance of social functioning. In this context, social frailty, as an important component of frailty, has gradually attracted increasing attention from scholars both in China and internationally and has become an emerging research focus in the field of aging. Social frailty refers to the state in which an individual is at increased risk of social vulnerability due to a sustained lack of social resources, social behaviors, social activities, and self-management abilities necessary to meet basic social needs (). Previous research on social frailty has primarily focused on community-dwelling older adults or general older adult populations with chronic diseases. However, older adults with type 2 diabetes are not simply a subgroup of the general older adult population. This group faces multiple stressors related to blood glucose control, long-term medication use, dietary restrictions, risk of complications, and hospitalizations (, ). These factors not only affect their physical function and psychological wellbeing but may also contribute to social frailty by limiting outdoor activities, reducing social engagement, increasing dependency on care, and undermining confidence in self-management (, ). Therefore, analyzing the factors associated with social frailty in older adults with type 2 diabetes can help extend social frailty research from the general older adult population to specific clinical groups with complex chronic disease management needs. At present, the current research pays relatively limited attention to the social frailty among older adults with type 2 diabetes, and there is a lack of relevant evidence for hospitalized patients. Hospitalized older adults with type 2 diabetes usually have more complex conditions and a heavier burden of complications, and their social participation and family support may differ from those of community-dwelling older adults. Therefore, by investigating the current status of social frailty among older adults with type 2 diabetes and analyzing its associated factors, this study aims to provide a scientific basis for targeted nursing interventions. It holds significant practical importance for reducing the risk of adverse outcomes among patients, alleviating the social and healthcare burden, and promoting healthy aging.