Ultrasound-induced blood-brain barrier opening in Alzheimer's disease: a systematic review of clinical studies.

As the country with the largest elderly population in the world, China is projected to have 400 million residents aged 65 years and older by 2050, thereby facing substantial challenges associated with population aging.Chronic diseases are the leading causes of death and disability among middle aged and elderly populations worldwide, imposing an unsustainable burden on health care systems across the globe.An epidemiological study found that more than 75.8% of Chinese residents aged 60 and above suffer from at least one chronic disease.Chronic diseases have emerged as a major global health challenge. The negative consequences of poor health, disability, and death impose an increasingly heavy economic burden, particularly in low and middle income countries. With the development of the economy and society, loneliness has become more prevalent among middle aged and elderly populations. Loneliness is defined as a subjective feeling of lacking adequate social relationships in terms of either quantity or quality.Loneliness is a major social risk factor for many adverse physical and mental health outcomes.Previous studies have demonstrated the associations between loneliness and diseases in adults, such as diabetes, pain, and cardiovascular diseases.However, relatively few studies have taken into account the impact of longitudinal changes in loneliness on the diseases of middle aged and elderly people. A cohort study from China has shown a significant association between loneliness trajectories and the risk of developing chronic obstructive pulmonary disease (COPD). Based on this, we conducted an analysis using the China Health and Retirement Longitudinal Study database (CHARLS). Our objective was to examine the associations between baseline loneliness, different longitudinal loneliness trajectory patterns, multiple chronic diseases, and the chronic comorbidity model. This study will clarify the long term impacts of persistent loneliness on physical health, provide reliable population level evidence for the role of psychosocial factors in the development of chronic diseases, and offer unique insights into clinical risk stratification, targeted psychological interventions, and the formulation of public health strategies for healthy aging in China.