Obesity and Smoking: A Tale of 2 Risk Factors with Implications for the Next Pandemic

Background In 1990, two risk factors that would figure prominently in the COVID-19 pandemic were on divergent paths in the US. The smoking rate was 23.5% and dropped to 13.5% in 2021, while the obesity rate was 11.5% and increased 186% to 33.0%. Objective The study objective was to compare the global impact of those risk factors on COVID deaths to help prepare the US for future pandemics. Methods Stata and Excel were used to regress global COVID deaths on obesity and smoking before and after vaccines were available, and US deaths/day were compared pre-and post-vaccines. Results Obesity was associated with global COVID deaths, with R 2 as high as 0.87 for cumulative data with slightly lower R 2 and coefficients for post-vaccines. For 9 regressions of deaths on obesity, all P values (overall and coefficients) were <0.05 while for regressions on smoking, no P values were < 0.05. Of the 1.1 million US deaths, the death rate/day post-vaccines was 59% of that pre-vaccines. If the US obesity rate had remained 11.5%, estimates suggest 800,000+ lives could have been saved. US smoking rate was reduced 42% by multiple strategies using support from a 1998 multi-billion-dollar settlement between states and tobacco companies. Conclusion Vaccines have limited ability to reduce total COVID deaths, with obesity remaining a key factor in death rates. Results suggest that lower obesity rates are needed to further reduce US COVID deaths, potentially saving thousands of lives in future pandemics. Lessons from reducing smoking rates might prove useful.