US Health Behaviors in the 21st Century Are Improving, but for Whom?

This is the authors' abstract. We don't add key points for this paper.

Over the last 20 years, focus on public health efforts to promote healthy behaviors while discouraging maladaptive ones has increased.Smoking cessation has received intense focus, and the Surgeon General 1 reported current smoking to be at an all-time low (14% prevalence) in 2020.Recent data have also increased awareness of the severe cardiovascular consequences associated with heavy alcohol intake. 2 While smoking and alcohol use are important, modifiable lifestyle factors, few recent, nationally representative data are available on longitudinal prevalence of both maladaptive and adaptive health behaviors.Even less is known about how these trends might vary among those of different socioeconomic strata.In JAMA Network Open, Li et al 3 provide an important contribution to our knowledge on how national public health efforts may have influenced health behaviors in the US over time.They used the continuous National Health and Nutritional Examination Survey (NHANES) data, 4 a serial crosssectional questionnaire that surveyed a representative sample of US residents 20 years or older from 1999 to 2020.The years 2017 to March 2020 were reweighted and combined to account for the COVID-19 pandemic.The authors examined all participants who had complete information for diet, exercise, body mass index, smoking, and alcohol use to assess whether behavior prevalence changed over time.These lifestyle factors were rigorously defined with validated instruments and scored according to guideline-directed thresholds for health (where applicable).They analyzed results both at the individual behavior level and a composite level (ie, the probability of reporting 3 healthy behaviors, 4 healthy behaviors, and so forth).This allows for nuance with particular behavioral trends while also assessing whether there might be differences in general healthy lifestyles over time.Because these data are nationally representative but also include biodemographic information such as age, sex, and race and ethnicity, the authors were able to robustly estimate population behaviors in key subgroups.All measures were collected using standardized, validated instruments that minimize recall bias, that is, the tendency for participants to overestimate engagement in healthy behaviors while underestimating their maladaptive behaviors.This should give confidence that the effects represent the true underlying behaviors.The authors estimated that, of the 47 852 participants analyzed, significant progress occurred in important, modifiable behaviors associated with overall health.The prevalence of those reporting never having smoked increased significantly from 49.4% (95% CI, 46.4%-52.4%) to 57.5% (95% CI, 55.5%-59.9%;P < .001)across the study period.Further, there was a meaningful, statistically significant increase in prevalence of adults reporting healthy diets (19.3% [95% CI, 16.0%-22.6%]to 24.5% [95% CI, 21.5%-27.5%];P < .001)and sufficient physical activity (55.7% [95% CI, 51.8%-59.6%] to 69.1% [95% CI, 67.2%-71.1%];P < .001).Healthy alcohol use prevalence was largely static over time, from 91.0% (95% CI, 89.4%-92.6%) to 92.4% (95% CI, 91.4%-93.4%).Despite these advances, healthy body weight prevalence significantly decreased over time (33.1% [95% CI, 30.5%-35.6%] to 24.6% [95% CI, 22.6%-26.7%];P < .001).Importantly, this study suggests that these trends varied significantly by age (younger adults more likely to improve lifestyle over time compared with older adults), educational level, race and ethnicity, and income level.Thus, socioeconomic background likely heavily influences the likelihood of developing healthy behaviors over time.The disparate trend of increasing obesity in the setting of increased healthy behaviors may be partially explained by residual recall bias but may also reflect poor understanding of a truly healthy diet.It may also be explained by population-level trends +