Medical Bulletin 31/July/2025 - Video

Exercise-based cardiac rehabilitation significantly reduces the severity, frequency, and recurrence of atrial fibrillation (AF), according to a pooled data analysis published in the British Journal of Sports Medicine. The study also found improvements in patients' exercise capacity and mental health, without any increase in serious side effects or mortality. These findings suggest that exercise-based rehab could be a valuable addition to existing atrial fibrillation treatment strategies.

Atrial fibrillation is the most common form of irregular heart rhythm, affecting millions globally and increasing the risk of stroke and heart failure. Exercise-based cardiac rehabilitation, which combines physical training with lifestyle education, medical risk management, and psychological support, is already widely used for heart attack and heart failure patients but has not been included in atrial fibrillation guidelines.

To assess its relevance for atrial fibrillation patients, researchers reviewed 20 randomized clinical trials conducted between 2006 and 2024, involving 2,039 participants from across Europe, Asia, Australia, North and South America, and Russia. Participants, mostly men with varying forms of AF, were followed for an average of 11 months. The interventions ranged from 8 to 24 weeks and included aerobic or combined aerobic and resistance training, with some trials also offering psychological or educational support.

The analysis found that exercise-based rehab led to a 39% reduction in symptom severity, a 43% reduction in frequency, and a 42% reduction in the duration of atrial fibrillation episodes. It also reduced recurrence risk by 32%. While overall mortality and serious side effects remained statistically unchanged, participants in the intervention groups showed significant gains in maximal oxygen intake and mental health scores.

“Collectively, these adaptations provide plausible mechanisms through which [exercise based rehab] not only supports general cardiovascular health and wellbeing but also gives atrial fibrillation specific benefits,” the authors stated. They concluded that “atrial fibrillation management guidelines should reflect this updated evidence base by recommending [exercise based cardiac rehabilitation] alongside drug and ablation therapies for patients with atrial fibrillation.”

Reference: Buckley BJ, Long L, Lane DA, et al

Exercise based cardiac rehabilitation for atrial fibrillation: Cochrane systematic review, meta-analysis, meta-regression and trial sequential analysis

British Journal of Sports Medicine Published Online First: 29 July 2025. doi: 10.1136/bjsports-2024-109149

Low Blood Sugar Before Pregnancy May Raise Risk of Preterm Birth, Low Birth Weight

Women with low blood sugar levels prior to conception may face an increased risk of adverse pregnancy outcomes, according to a new study published in PLOS Medicine. The large-scale analysis draws from health data on more than 4.7 million Chinese women and sheds light on the implications of preconception hypoglycemia.

Glucose serves as the body’s primary energy source, and maintaining normal levels is essential for overall health. While the risks of high and low blood sugar during pregnancy are well-documented, little is known about the potential effects of low blood sugar (hypoglycemia) before pregnancy in women without pre-existing diabetes. Previous studies have mainly focused on hypoglycemia during pregnancy, leaving a knowledge gap that this study aimed to fill.

Researchers conducted a retrospective analysis using data from the National Free Preconception Checkup Project, a government-supported health initiative in China. Between 2013 and 2016, they reviewed health records of 4,866,919 women planning to conceive, including 239,128 women identified with preconception hypoglycemia. Their pregnancy outcomes were then compared to those with normal blood glucose levels.

The analysis found that women with hypoglycemia before pregnancy were more likely to experience adverse outcomes such as preterm birth, low birth weight, and birth defects. These women were generally younger and more likely to fall into the underweight BMI category. Interestingly, the impact of hypoglycemia varied with BMI: underweight women faced a higher risk of miscarriage, while overweight women had a reduced risk of delivering a baby large for gestational age.

The authors state, “In addition to paying attention to women with preconception hyperglycemia, our findings call for increased concern for women with hypoglycemia in preconception glycemic screening. These findings emphasize the importance of preconception examination in preventing and managing reproductive health risks for all women planning to conceive, and also highlight the necessity of comprehensive screening and coordinated interventions for abnormal FPG (fasting plasma glucose) prior to and during pregnancy, which is crucial for advancing the intervention window and mitigating the risk of adverse pregnancy outcomes.”

Reference: u H, Yang Y, Zhao C, Lyu X, Li J, Lei J, et al. (2025) Preconception hypoglycemia and adverse pregnancy outcomes in Chinese women aged 20–49 years: A retrospective cohort study in China. PLoS Med 22(7): e1004667. https://doi.org/10.1371/journal.pmed.1004667

Study Reveals Cannabis Use Disorder Linked to Three Times Higher Risk of Oral Cancer

A new study published in Preventive Medicine Reports by researchers at the University of California San Diego School of Medicine suggests that individuals diagnosed with cannabis use disorder are more than three times more likely to develop oral cancer within five years than those without the disorder. The findings raise new concerns about the long-term health implications of problematic cannabis use as legalization and daily consumption become more widespread.

With 17.7 million people reporting daily or near-daily cannabis use in 2022, understanding the associated health risks has become increasingly urgent.

To assess the relationship between cannabis use disorder and oral cancer, researchers analyzed electronic health records from over 45,000 patients. Of those, 949 had been diagnosed with cannabis use disorder. After adjusting for variables such as age, sex, body mass index, and smoking status, individuals with cannabis use disorder were found to have a 325% increased risk of developing oral cancer within five years compared to those without it. The risk was even higher 624% among tobacco smokers with cannabis use disorder compared to tobacco smokers without cannabis use disorder.

“Cannabis smoke contains many of the same carcinogenic compounds found in tobacco smoke, which have known damaging effects on the epithelial tissue that lines the mouth,” said study author Raphael Cuomo, Ph.D., associate professor in the Department of Anesthesiology at UC San Diego School of Medicine. “These findings add to a growing body of evidence suggesting that chronic or problematic cannabis use may contribute to cancer risk in tissues exposed to combustion products.”

Even after accounting for tobacco use, the link between CUD and oral cancer remained strong, suggesting additional factors such as THC’s immune-suppressing effects could be involved. The study underscores the importance of integrating oral health screening and education into substance use disorder care. Further research is needed to understand the mechanisms behind this association and to guide future public health messaging.

Reference: Cuomo, R. E. (2025). Cannabis use disorder and five-year risk of oral cancer in a multicenter clinical cohort. Preventive Medicine Reports, 103185.