Research highlights how lifestyle can overcome genetic obesity risks

A groundbreaking study published in “Cell Metabolism” has illuminated the powerful role of lifestyle modifications in mitigating the genetic predisposition to obesity, revealing new avenues for managing this global health challenge.

Obesity has reached pandemic proportions, exacerbated by inactive lifestyles and the consumption of high-calorie diets. The condition is influenced by both heritable and polygenic factors, with numerous metabolic pathways and over a thousand genetic variants playing roles. Traditionally, it was assumed that one’s genetic risk for obesity was unalterable.

Recent gene-environment studies have hinted that certain lifestyle choices might lessen the influence of specific genes linked to obesity. These studies, however, typically focused only on limited genes and lifestyle factors, leaving a gap in understanding the broader interaction between lifestyle habits and genetic predispositions.

This latest research delved into whether lifestyle changes could indeed counteract genetic risks. The study cohort included 338,600 white British participants from the UK Biobank, refined to 337,554 after excluding those lacking essential data. Researchers calculated a polygenic score (PGS) from a genome-wide association study on body mass index (BMI) specific to individuals of European descent. They also developed a healthy lifestyle score based on five factors: alcohol consumption, sleep duration, sedentary behaviour, diet, and physical activity. The study’s primary focus was on new obesity cases, with existing obesity cases as a secondary focus.

The researchers predicted absolute risks using odds ratios (ORs) and hazard ratios (HRs) for both new and existing obesity, relative to PGS percentile and lifestyle factors. These ratios were derived from Cox proportional hazard and logistic regression models. They also calculated the probability of developing obesity by age 75 and identified new obesity-related morbidities (ORMs) from various health data sources.

Analyses showed that high genetic risk and unhealthy lifestyle habits were each linked to higher obesity risks, both independently and combined. The risk was most pronounced in those with both high genetic predisposition and poor lifestyle habits, with a HR of 3.54 compared to those with low genetic risk and healthy lifestyles.

Interestingly, the median likelihood of obesity by age 75 varied significantly with lifestyle: 2.8% in those with poor lifestyles versus 1.7% in those with healthier choices. This pattern was echoed in the analysis of existing obesity cases.

The study also found significant additive interactions between lifestyle and genetic risk in terms of obesity incidence, with consistent results from multiplicative interaction analysis. Importantly, sedentary behaviour was linked to the highest obesity risk, regardless of genetic background. Conversely, individuals with high genetic risk but who maintained healthy lifestyles had similar ORMs to those with lower genetic risk.

Overall, the study underscores the profound impact of healthy lifestyle choices in reducing the risk of obesity and its related health issues, even among those with a high genetic predisposition. These findings advocate for the promotion of active, health-conscious behaviours across all genetic backgrounds as a critical strategy in combating obesity.

This research not only challenges the fatalistic view of genetic determinism but also highlights the empowering role of personal lifestyle choices in managing one’s health.