Medical Bulletin 22/ May/ 2024

In a study published in the journal Toxicological Sciences, University of New Mexico researchers have detected significant concentrations of microplastics in the testicular tissue of both humans and dogs, a+dding to growing concern about their possible effect on human reproductive health.

Microplastics are tiny plastic particles, less than 5 millimetres in size, that result from the breakdown of larger plastic debris or are manufactured for use in products like cosmetics and cleaning agents. These particles are pervasive in the environment, infiltrating air, water, and food supplies.

Emerging research suggests that microplastics may pose health risks to humans, potentially causing inflammation, disrupting hormones, and contributing to the development of diseases due to their chemical composition and the pollutants they may carry.

In the study, Xiaozhong John Yu, a professor in the UNM College of Nursing and his team, obtained anonymized human tissue from the New Mexico Office of the Medical Investigator, which collects tissue during autopsies and stores it for seven years before disposal.

The team chemically treated the samples to dissolve the fat and proteins and further heated the samples as different types of plastic burned at specific temperatures.

The results showed that in canines, the average concentration of microplastics in testicular tissue was 122.63 micrograms per gram of tissue. In human tissue, the average concentration was 329.44 micrograms per gram – nearly three times higher than in canines and significantly higher than the average concentration found in placental tissue.

The researchers identified polyethylene (PE), commonly used to make plastic bags and bottles, as the most prevalent polymer in both human and canine tissue.

“Compared to rats and other animals, dogs are closer to humans. Physically, their spermatogenesis is closer to humans and the concentration has more similarity to humans. Our study revealed the presence of microplastics in all human and canine testes. The team was also able to quantify the amount of microplastics in the tissue samples that revealed correlations between certain types of plastic and reduced sperm count in the canine samples,” said Yu.

Reference: Chelin Jamie Hu, Marcus A Garcia, Alexander Nihart, Rui Liu, Lei Yin, Natalie Adolphi, Daniel F Gallego, Huining Kang, Matthew J Campen, Xiaozhong Yu, Microplastic presence in dog and human testis and its potential association with sperm count and weights of testis and epididymis, Toxicological Sciences, 2024;, kfae060, https://doi.org/10.1093/toxsci/kfae060

In a recent study published in The Journal of Nutrition, Health and Aging, researchers investigated the associations between dietary patterns and lung cancer risk in a large cohort of older adults.

Specifically, they evaluated the change in lung cancer hazard ratios given the long-term (~8.8 years) consumption of different fat components (saturated, unsaturated [mono and poly]).

Lung cancer stands as one of the most significant non-communicable diseases worldwide, contributing substantially to mortality rates. In 2020 alone, the Global Cancer Observatory reported a staggering 2.2 million new cases and 1.8 million deaths attributed to lung cancer.

While smoking remains a primary risk factor, recent attention has shifted towards exploring the impact of lifestyle factors, including sleep habits and dietary choices, on lung cancer incidence and progression. Previous studies have shed light on the potential protective effects of dietary elements such as fibre, fruits, and vitamin C against lung cancer development. Conversely, dietary fat intake has been implicated in lung cancer pathology, with low-fat diets emerging as a potential strategy for reducing risk.

In the study, researchers examined the long-term outcomes of various fat intake levels on lung cancer and its subtypes within a large cohort. They introduced a new Low-Fat Diet (LFD) score, calculated based on the proportion of calories obtained from fats relative to those from proteins and carbohydrates.

The study cohort was drawn from the Prostate, Lung, Colorectal, and Ovarian Cancer Screening Trial. Data collection involved baseline health assessments and subsequent annual questionnaires.

The analysis of Low-Fat Diet (LFD) adherence strata showed that older individuals, and female participants exhibited the highest levels of adherence to low-fat diets. Throughout the 8.83-year follow-up period, 1,642 patients were diagnosed with lung cancer.

The findings indicated that saturated fatty acids could significantly elevate the risk of lung cancer, while no such correlations were found for monounsaturated or polyunsaturated fatty acids (PUFA). Interestingly, the most substantial benefits of polyunsaturated fatty acids were observed in subgroups with a history of smoking, despite their heightened risk of lung cancer contraction.

“Regards to dietary fatty acids, high consumption of saturated fatty acids may contribute to an increased risk of lung cancer, with a higher risk observed for small cell lung cancer in particular. Therefore, our findings support the potential benefits of adhering to low fat diet and reducing saturated fatty acids intake as a strategy for preventing lung cancer,” said the study authors.

Reference: Peng, L., Du, Q., Xiang, L., Gu, H., Luo, H., Xu, Z., He, H., Xia, B., Zhou, Z., Wang, Y., & Chen, Y. (2024). Adherence to the low-fat diet pattern reduces the risk of lung cancer in American adults aged 55 years and above: a prospective cohort study. In The Journal of nutrition, health and aging (Vol. 28, Issue 7, p. 100240). Elsevier BV, DOI – 10.1016/j.jnha.2024.100240,

According to a new study led by a University of Florida College of Public Health and Health Professions researchers, higher fluoride levels in pregnant women are linked to increased odds of their children exhibiting neurobehavioral problems at age 3.

The findings were published in the journal JAMA Network Open.

Exposure to fluoride during pregnancy has been associated with potentially harmful effects on children's neurobehavioral development. The developing fetal brain is particularly vulnerable to environmental exposures, and fluoride has been shown to cross the placental barrier and interfere with neurodevelopmental processes.

Studies have suggested that higher levels of fluoride exposure during pregnancy may lead to adverse neurodevelopmental outcomes, including lower cognitive function, decreased IQ scores, and increased risk of attention deficit hyperactivity disorder (ADHD) symptoms.

In the study, researchers utilised data from the Maternal and Developmental Risks from Environmental and Social Stressors study to examine the impact of fluoride exposure during pregnancy on children's neurobehavioral development.

They collected urine samples from participants in their third trimester and assessed urinary fluoride levels, a common measure of fluoride exposure. To ensure accurate results, the researchers also accounted for potential lead contamination from water pipes.

When the children reached age 3, their mothers completed the Preschool Child Behavior Checklist, revealing that higher fluoride exposure during pregnancy was associated with increased neurobehavioral problems in the children.

“There is no known benefit of fluoride consumption to the developing fetus. But we do know that there is possibly a risk to their developing brain. We found that each 0.68 milligrams per litre increase in fluoride levels in the pregnant women’s urine was associated with nearly double the odds of children scoring in the clinical or borderline clinical range for neurobehavioral problems at age 3, based on their mother’s reporting,” said study’s lead investigator Ashley Malin.

Reference: Malin AJ, Eckel SP, Hu H, et al. Maternal Urinary Fluoride and Child Neurobehavior at Age 36 Months. JAMA Netw Open. 2024;7(5):e2411987. doi:10.1001/jamanetworkopen.2024.11987