Study links fathers' nicotine use to altered metabolism in children

A new mouse study suggests nicotine exposure in fathers before conception may alter how their children process sugar and metabolism, potentially raising diabetes risk in the next generation

Could a father’s smoking or nicotine use affect his children’s health in the future? 

Researchers at the University of California, Santa Cruz, found that when male mice were exposed to nicotine before reproduction, their offspring showed changes in how their bodies handled sugar and metabolism. The study titled Exposure of male mice to nicotine leads to metabolic dysfunction in their male and female offspring, published in the Journal of the Endocrine Society, suggests that paternal nicotine use could influence diabetes risk in the next generation by changing metabolic pathways linked to insulin, liver function, and glucose processing. 

The scientists observed metabolic changes in both male and female offspring of nicotine-exposed fathers. According to them, the results highlight the importance of paternal health before conception, an aspect often overlooked in discussions about reproductive and child health.

 

What did the study find about fathers’ nicotine exposure?

The study investigated how nicotine exposure in male mice affected the metabolic health of their offspring. Male mice were given nicotine in their drinking water for six weeks, a duration that covers the full cycle of sperm development, before mating with unexposed female mice. 

Researchers then examined the metabolism of the next generation. They found notable changes in how the offspring processed glucose and regulated hormones linked to metabolic health. 

These findings suggest that paternal nicotine exposure can trigger metabolic changes in offspring even when the offspring themselves were never exposed to nicotine. 

The study reported sex-specific metabolic changes in the offspring. 

Female offspring of nicotine-exposed fathers showed:

• Lower fasting blood glucose levels
• Reduced insulin levels
• Faster glucose clearance during glucose tolerance tests

These changes suggest that paternal nicotine exposure may alter insulin signalling pathways and glucose uptake in tissues such as adipose (fat) tissue. 

Male offspring showed a different pattern:

• They did not display major changes in glucose tolerance
• Researchers detected alterations in liver-related metabolic pathways and hormone levels, including lower insulin and glucagon levels

Together, the results suggest that paternal nicotine exposure can influence metabolic regulation differently in male and female offspring. 

The study also examined gene activity in key metabolic organs, including the liver and adipose tissue. Scientists discovered changes in genes involved in several metabolic pathways, including:

• Insulin signalling
• Fat metabolism
• Glucagon signalling
• Peroxisome proliferator-activated receptor (PPAR) pathways, which regulate lipid metabolism and energy balance

In male offspring, liver gene analyses suggested a reduced ability to adapt to fasting and mobilise energy. This impaired metabolic flexibility could potentially increase susceptibility to metabolic disorders later in life. 

Female offspring, meanwhile, showed gene expression changes in fat tissue that may enhance glucose uptake. 

Much research on pregnancy and child health focuses on maternal exposures during pregnancy. However, this study highlights that fathers’ health and lifestyle before conception may also influence offspring health. Senior author Raquel Chamorro-Garcia, PhD, noted in the statement available on the UC Santa Cruz website, “Considering the evidence that male exposure can increase the likelihood of their children developing chronic diseases, it is crucial to incorporate male health into preconception care.” 

Does fathers’ smoking increase diabetes risk in children?

The researchers caution that this study was conducted in mice, and further research is needed to determine whether similar effects occur in humans. 

However, the findings add to a growing body of evidence suggesting that environmental exposures, including smoking, diet, and toxins, may affect health across generations through biological changes in sperm and gene regulation. 

Future studies will need to examine whether these metabolic alterations persist into adulthood and whether they increase the likelihood of obesity, insulin resistance, or type 2 diabetes later in life. 

The study highlights that reproductive health is not just about mothers. Fathers’ lifestyle choices also influence the long-term health of future children.