Trends in the prevalence of individual health risk factors: how has the mortality risk changed over time?

In a recent study published in the PLOS ONE Journal, researchers explored the prevalence of health risk factors and their correlation with all-cause mortality.

Study: Is anyone truly healthy? Trends in health risk factors prevalence and changes in their associations with all-cause mortality. Image Credit: gbeerredhot/Shutterstock.com

Background

Public health and research have commonly aimed to monitor known risk factors through surveillance. Cancer and cardiovascular disease (CVD) remain the top mortality causes in the United States. However, the incidence of CVD mortality has decreased over the years.

Social and lifestyle factors have been linked to the risk of developing cancer and CVD. Yet, the potential changing correlation between risk factors, mortality, and morbidity over time has received little attention.

About the study

In the present study, researchers identified patterns in the occurrence of health risk factors over time and analyzed whether their correlation with mortality has changed.

The study compared two nationally representative samples from 1988-1994 and 1999-2014 with a five-year mortality follow-up in a cross-sectional manner.

Data from National Health and Nutrition Examination Surveys (NHANES) III was used to obtain participant information, which was continuously collected from 1999 to 2014 to ensure a five-year mortality follow-up. The data was gathered through home interviews and health assessments conducted at Mobile Examination Centers (MEC).

Individuals aged 20 years or older were eligible for inclusion in the analytical sample. Risk factors were categorized as the presence or absence of any of the risk factors from these four categories:

1. Lifestyle- high-fat diet, no physical activity, alcohol intake, current smoking;
2. physiological- hyperglycemia, high blood pressure, dyslipidemia, cardiovascular disease, cancer, and lung problems;
3. social or mental- low education, lack of health insurance, food insecurity, low income, and reliance on mental health medication;
4. physical- the use of pain medication, arthritis, obesity, limitations in performing daily activities.

Results

The team noted that 18 out of 19 health risk factors among men and/or women reported changes in prevalence over time. At all time points, more than 97% of individuals reported a minimum of one of the 19 risk factors, and there was no change in the prevalence of experiencing any risk factor over time.

The prevalence of self-reported 'poor' health decreased slightly over the study period among men and women, with no difference between the sexes.

From 1988-1994 to 2011-2014, there was an increase in the occurrence of lifestyle, social/mental, and physical risk factors. However, the prevalence of physiological risk factors decreased during the same time.

Women were generally more likely than men to have physical and lifestyle risk factors. In contrast, no sex-related differences existed for physiological, social/mental, or other health risk factors. The prevalence of physical inactivity and excessive alcohol intake increased among individuals in terms of lifestyle factors.

However, smoking decreased in both men and women while consuming a high-fat diet declined from 49% to 44% in men only.

High blood pressure, high glucose, and cancer prevalence increased among physiological risk factors, while high lipids decreased. The prevalence of CVD decreased between NHANES III and NHANES continuous 1999-2000 before rising and being generally more inferior in 2011-2014 than NHANES III among women.

On the other hand, the prevalence of lung disease did not change over time. Most persons who did not have health insurance experienced food insecurity and consumed mental health medications increased. At the same time, there was a reduction in the prevalence of individuals having less than a high school education.

The prevalence of physical risk factors such as pain medication use, arthritis, and obesity increased significantly over time for men and women. However, there was a reduction in ADL problems among adults aged over 60 years.

During the five-year follow-up period, a total of 1,319 deaths occurred. Individuals who did not possess any of the 19 risk factors did not experience any fatalities. In NHANES continuous, the presence of any risk factors was linked to a 30% decrease in the likelihood of five-year mortality compared to NHANES III.

Conclusion

The study revealed that changes in social programs, healthcare, and the built environment may have impacted the relationship between traditional risk factors and health/mortality.

The changes make it difficult to analyze trends over time and hence require careful interpretation of health trends according to surveillance data. The researchers believe that future studies must focus on the evolving prevalence of conventional risk factors and analyze how these factors are linked to illness and death.

Written by

Bhavana Kunkalikar

Bhavana Kunkalikar is a medical writer based in Goa, India. Her academic background is in Pharmaceutical sciences and she holds a Bachelor's degree in Pharmacy. Her educational background allowed her to foster an interest in anatomical and physiological sciences. Her college project work based on ‘The manifestations and causes of sickle cell anemia’ formed the stepping stone to a life-long fascination with human pathophysiology.