U.S. overdose deaths fell for the first time in years; vitamin D may boost chemo response in breast cancer; sleep apnea may be under-diagnosed in female athletes – Morning Medical Update

U.S. drug overdose deaths fell for the first time in years

A study published in JAMA Network Open finds that U.S. drug overdose death rates began a sustained decline in August 2023, dropping for 15 consecutive months. Opioid-related deaths fell more rapidly than stimulant-related deaths. But not all groups saw improvement — older adults and racial minorities including Black, Hispanic and American Indian individuals continued to see rising rates, though increases slowed. Researchers say the shift likely reflects a mix of harm reduction efforts, market changes and population-level factors, but caution that crisis-level disparities remain.

Vitamin D may boost chemo response in breast cancer

Women with breast cancer who took low-dose vitamin D supplements during chemotherapy were nearly twice as likely to see their tumors disappear compared to those who received a placebo, according to a study from São Paulo State University. The six-month study found 43% of patients on vitamin D achieved complete response, vs. 24% in the control group.

Sleep apnea may be under-diagnosed in female athletes

A new study presented at the American College of Cardiology (ACC)’s 2025 Care of the Athletic Heart conference found that one in four female college athletes showed signs of mild sleep apnea — despite being young, fit and asymptomatic. The study noted higher rates in those with greater lean mass and stiffer arteries, suggesting a potential relationship with intense training.