A meta-analysis has shown that loneliness and social isolation could increase the risk of premature death.

Loneliness and social isolation have been associated with a higher risk of early death, according to a comprehensive meta-analysis involving over 2 million adults, as reported in the journal Nature Human Behavior.

The study, published on Monday, aimed to address previous conflicting results by analyzing data from 90 studies conducted worldwide. The researchers followed participants for durations ranging from six months to 25 years.

The study found that individuals experiencing social isolation face a 32% greater risk of premature death from any cause when compared to their socially connected counterparts. Moreover, participants who reported feelings of loneliness were found to be 14% more likely to die prematurely compared to those who did not experience loneliness.

Julianne Holt-Lunstad, a psychology and neuroscience professor at Brigham Young University and lead scientist for the U.S. Surgeon General's advisory report on social isolation and loneliness, commended the study. Though not involved in the meta-analysis, she told CNN that it provides further confidence regarding the significance of social isolation and loneliness as independent risk factors for premature death.

The analysis distinguished between social isolation and loneliness. Social isolation is defined as an objective lack of contact with others, which may involve having a limited social network or living alone. On the other hand, loneliness refers to the subjective distress arising from a perceived discrepancy between desired and actual social relationships.

Holt-Lunstad emphasized that despite the prevalent assumption that voluntary isolation is harmless or even beneficial, the findings confirmed and expanded on previous research, demonstrating the risks associated with social isolation irrespective of feelings of loneliness.

Turhan Canli, a professor of integrative neuroscience at Stony Brook University, suggested that social isolation and loneliness can be considered forms of chronic stress, which can negatively impact health. In a dialogue with CNN, Canli pointed out that stress hormones released in response to chronic loneliness or social isolation can have adverse effects on the body.

The meta-analysis also explored the connection between loneliness, social isolation and mortality in individuals with cardiovascular disease or breast or colorectal cancer. The study showed that socially isolated participants with cardiovascular disease were more likely to die prematurely than those without the disease. Additionally, socially isolated individuals with breast cancer faced a higher risk of mortality from the disease when compared to their socially connected counterparts.

The Centers for Disease Control and Prevention (CDC) also reported how social isolation and loneliness could increase the risk for numerous conditions, including heart disease, stroke, type 2 diabetes, depression and anxiety, self-harm and dementia, among others.

Canli suggested that lifestyle behaviors might contribute to premature death among socially isolated or lonely individuals. Factors such as smoking, alcohol use, poor diet and lack of exercise are more prevalent among those who experience social isolation or loneliness.

Experts said several reasons why social isolation appears to have a stronger impact on the risk of premature death than loneliness alone. While lonely individuals may have mental health stress, having social networks — even if they are not entirely fulfilling — can offer some resilience. Furthermore, individuals with limited social networks or infrequent contact with others may be less likely to receive necessary medical care.

While the meta-analysis underscored the detrimental effects of social isolation and loneliness, experts emphasized the need to explore the interplay between these factors for a deeper understanding and effective interventions.