Low sexual activity, body shape, and mood may combine in ways that shorten lives, new study suggests

People in the United States who have sex fewer than a dozen times a year appear more likely to die during follow-up if they carry extra abdominal fat or score high on a standard test of depression symptoms, according to a study in the Journal of Affective Disorders. The work, which tracked nearly five thousand adults over fifteen years, indicates that a wide waist and depressed mood may amplify each other’s harmful effects, raising death risk beyond what either factor predicts on its own.

The research team set out to understand why sparse sexual activity so often accompanies poor health outcomes. Earlier population surveys have shown that low sexual frequency is linked to higher rates of obesity, cardiovascular disease, diabetes, and early death. Yet it remained unclear which specific biological or psychological traits best mark that heightened danger, and whether those traits interact in a way that makes the whole risk greater than the sum of its parts. By pinpointing modifiable warning signs, the authors hoped to guide physicians toward tailored prevention strategies for a group that has received little clinical attention.

To explore these questions, the investigators drew on the National Health and Nutrition Examination Survey, an ongoing program that combines interviews, physical examinations, and long-term mortality tracking. They pooled six survey cycles collected between 2005 and 2016 and focused on 4,978 participants aged twenty to fifty-nine who reported having vaginal or anal sex fewer than twelve times in the previous year. Respondents lacking a sexual partner, those with intellectual impairments, and those with missing key data were excluded to keep the analysis consistent.

Each participant answered the nine-item Patient Health Questionnaire, a widely used screening tool for depressive symptoms. A score of ten or higher flagged probable depression. The researchers also calculated five different measures of body fat distribution. Traditional body mass index, which relates weight to height, was included, but they paid special attention to A Body Shape Index. This newer metric combines waist circumference, height, and weight to capture abdominal fat more precisely than body mass index alone.

Deaths from any cause up to December 31, 2019 were confirmed through linkage to the National Death Index. The median follow-up time was just over two years, and the maximum was fifteen. In total, 215 participants—about four percent of the sample—died during that period.

Statistical models that accounted for age, sex, race, smoking, alcohol use, blood pressure, kidney function, diabetes, and other potential confounders revealed that A Body Shape Index stood out as the strongest predictor of mortality among the five fat-related measures. A value of 0.082 or higher defined the high-risk group. People at or above that threshold were nearly twice as likely to die as peers with smaller waists, even after adjustments.

Depression carried a similar weight. Participants who screened positive were eighty-six percent more likely to die than those with lower scores. Most striking, though, was what happened when both factors appeared together. Individuals who had a wide waist and met criteria for depression faced almost quadruple the death risk of those who had neither.

An interaction analysis estimated that roughly half of the deaths in this high-risk subgroup could be attributed to the combined influence of abdominal fat and depressive symptoms, meaning the two conditions seem to magnify each other rather than operate independently.

Survival curves painted a stark picture. Among men with both risk factors, only about seventy-six percent were alive at fifteen years, compared with ninety-one percent of similarly affected women. The sex gap echoes laboratory findings that male endothelial cells in fat tissue show more inflammatory and aging-related gene activity than female cells, which may leave men more vulnerable to the vascular damage associated with obesity. Depression may widen the divide, as men often delay care and present with more severe symptoms than women by the time they reach treatment, potentially worsening outcomes.

The team then built a practical tool clinicians could use to estimate survival odds in this population. Feeding ten easily obtained variables—sex, race, hypertension, diabetes, smoking, waist-based body shape index, sexual frequency, heart disease history, depression score, and age—into a machine-learning method called least absolute shrinkage and selection operator, they produced a nomogram that predicted three-, five-, and ten-year mortality with an accuracy of about seventy-eight percent. Such a chart could help physicians and counselors decide when to prioritize weight management, mental health care, or sexual health interventions during routine visits.

But the study, like all research, has some caveats. Sexual activity was self-reported, raising the possibility of recall errors or underreporting, especially for a sensitive topic. Because the survey asked only broad frequency categories, the threshold of fewer than twelve encounters per year lumped together people who never have sex with those who do so monthly.

The observational design also means the study cannot confirm cause and effect. Abdominal fat and depression might lead to lower sexual frequency, or the absence of sexual intimacy and its psychological benefits might worsen mood and metabolic health. Future investigations that track changes in these factors over time, or that test targeted interventions, are needed to untangle directionality.

It is also worth noting that the sample represents the United States. Cultural norms around body image, mental health, and sexual behavior differ worldwide, so studies in other countries are required before generalizing the findings. Finally, individuals without a sexual partner were not included, yet they may share health challenges with the low-frequency group.

Despite these limitations, the study highlights two straightforward signals—waist size adjusted for height and weight, and depressive symptoms—that clinicians can measure during a single office visit. When they appear together in adults who rarely have sex, the combination seems to foreshadow a markedly shorter life span. Screening for both factors, and addressing them in tandem, may provide a new path to improving longevity among people whose intimate lives are quieter than average but whose health risks demand louder attention.

The study, “Synergistic effects of a body shape index and depression on mortality in individuals with low sexual frequency,” was authored by Tian-Qi Teng, Meng-Meng Wang, De-Gang Mo, Yan-you Xie, Rui Chen, Jia-Chao Xu, Jing Liu, and Hai-Chu Yu.