Association between opium consumption and sarcopenia in middle-aged and older adults: findings from the Fasa Adults Cohort Study (FACS)

Why this matters for everyday health

Sarcopenia—age-related loss of muscle—doesn’t just make people weaker; it raises the risk of falls, fractures, disability, and even early death. At the same time, opium and other opioids are widely used in many parts of the world, both medically and non‑medically. This study from southern Iran asks a simple but important question: does long‑term opium use make people more likely to lose muscle? The answer, drawn from thousands of adults, suggests that it does—especially for men—and that muscle health should be part of how we think about the harms of opioids.

Muscle loss as a hidden burden of aging

Doctors now view sarcopenia as a disease in its own right, not just “getting old.” It is common in people over 60 and is closely tied to frailty, falls, broken bones, and higher health‑care costs. In Iran, as in many countries, a sizable fraction of older adults already live with low muscle mass, often alongside obesity or chronic illnesses. Because sarcopenia can be slowed by exercise, diet, and other measures, researchers are eager to pinpoint everyday exposures that might quietly accelerate muscle loss—and that could potentially be changed.

Why opium is under the spotlight

Opium, derived from the poppy plant, has long been used in Iran and remains common in some communities. Modern research shows that chronic opioid use can disrupt the body’s hormone system, particularly the pathway that controls sex hormones such as testosterone. In men, low testosterone is known to reduce muscle building and favor fat gain. Animal and clinical studies also suggest opioids can directly weaken muscles and reduce physical performance. Yet, before this work, no study had directly examined whether people who use opium are more likely to have sarcopenia.

How the study was done

The researchers analyzed data from nearly 4,000 adults aged 35 to 70 years taking part in the Fasa Adult Cohort Study in rural southern Iran. All participants had their body composition measured with a bioelectrical impedance device, which estimates lean tissue in the arms and legs. People whose skeletal muscle index fell in the lowest 40% of the group were classified as having sarcopenia. Opium use was assessed through detailed face‑to‑face interviews that captured whether participants used opium regularly and how much they had consumed over their lifetime. The team also gathered extensive information on diet, physical activity, smoking, medical history, and medications, allowing them to mathematically adjust for many other influences on muscle health.

What the researchers found

After accounting for age, sex, smoking, blood pressure, liver fat, thyroid disease, diet‑related inflammation, calcium intake, and markers of systemic inflammation, regular opium use was linked to 76% higher odds of having sarcopenia. This pattern held across many subgroups, including people with both low and high physical activity, different income levels, and lower protein intake. The association was clearest in men: male opium users were significantly more likely to have low muscle mass, while the pattern in women was weaker and statistically uncertain, possibly because of hormonal and cultural differences in use. Among users themselves, those who had accumulated higher doses of opium over the years showed a modest but measurable rise in sarcopenia risk with each step up in exposure.

Clues to how opium may thin muscles

The authors argue that several mechanisms probably act together. Long‑term opioid exposure can suppress the brain–hormone axis that normally stimulates the testes to make testosterone. Lower testosterone tips the balance away from building muscle toward breaking it down, and may also reduce protection against low‑grade inflammation that harms muscle tissue. Opioids can directly affect nerves and muscles, dampening strength and everyday activity, which in turn promotes disuse‑related wasting. Interestingly, the link between opium and low muscle was strongest in people without major chronic diseases and in those whose diets were less inflammatory, suggesting that in otherwise relatively healthy bodies, opioid‑related hormonal and neuromuscular effects stand out more clearly.

What this means in practical terms

Because the study looked at a single point in time, it cannot prove that opium use causes muscle loss, and it relied on self‑reported drug histories rather than blood tests or scans of hormone levels. Still, the large sample, careful exclusions, and dose‑related pattern make a compelling case that opium may be an overlooked driver of declining muscle in middle‑aged and older adults, particularly men. For communities where opium use is common, the findings suggest that routine checks of muscle health—and early steps such as resistance exercise, adequate protein intake, and, when appropriate, hormone and addiction care—should be woven into strategies to help people reduce or quit opioids. More broadly, the work adds muscle loss to the growing list of long‑term harms that societies must weigh when confronting the opioid epidemic.

Citation: Bazmi, S., Masrour, F., Farjam, M. et al. Association between opium consumption and sarcopenia in middle-aged and older adults: findings from the Fasa Adults Cohort Study (FACS). Sci Rep 16, 10430 (2026). https://doi.org/10.1038/s41598-026-40992-8

Keywords: sarcopenia, opium use, muscle loss, opioids and hormones, aging health