Metabolic syndrome (MetSyn) is a common condition among U.S. adults, affecting approximately 100 million individuals.

MetSyn is strongly related to an increased risk of developing type 2 diabetes and other adverse health conditions. There are 5 components of MetSyn: Low HDL-cholesterol, elevated blood triglyceride level, elevated resting blood pressure, elevated fasting blood glucose level, and high waist circumference. Individuals with 3 or more of these 5 components are defined as having MetSyn.

Vitamin D deficiency and low levels of cardiorespiratory fitness (CRF) are also quite common in the U.S. population, and are each strongly related to a number of adverse health conditions as well. In a recent Cooper Institute study, we systematically examined the relationship between CRF, blood vitamin D levels, and the risk of having MetSyn in adult men.

We used a sample of 14353 men who completed a comprehensive health examination at the Cooper Clinic in Dallas TX, including CRF measurement based on a maximal treadmill test, as well as measures of blood vitamin D levels and MetSyn components. Participants were classified into groups of low (unfit), moderate, and high CRF by age group, as well as by standard cut points for blood vitamin D level and MetSyn.

Our main findings were as follows:
 

• Overall, about 22% of the men had MetSyn.
• Men with MetSyn had significantly lower levels of vitamin D than men without MetSyn.
• When compared with unfit men, moderate and high fit men were 69% and 92% less likely to have MetSyn, respectively.
• When compared with men who were vitamin D deficient, men with normal vitamin D levels were 71% less likely to have MetSyn.
• Within each of the 3 categories of blood vitamin D, moderate and high fit men had substantially lower risk of having MetSyn than unfit men. See Figure below.
  
  
  

Let’s discuss the findings in the Figure. You will see that among men who were vitamin D deficient, the rates of metabolic syndrome were about 70% and 30% in unfit and fit men, respectively. Among men who were vitamin D insufficient, the rates were about 55% and 20%, respectively. Finally, among men with normal vitamin D levels, the rates of MetSyn were about 45% and 15% in unfit and fit men, respectively. In summary, among adult men, higher levels of CRF and blood vitamin D were strongly related to a decreased risk of having MetSyn. Furthermore, within each vitamin D category, fit men were significantly less likely to have MetSyn than unfit men.

Action Plan

• All men are urged to undergo a measure or estimate of their CRF. Men with low CRF should strive to attain at least a moderate level of CRF.

• All men are urged to meet the 2018 Physical Activity Guidelines for Americans. The Guidelines recommend accumulating a minimum of 150 minutes each week of moderate intensity aerobic activity (e.g. brisk walking). Additionally, a minimum of 2 days each week of strength training is recommended in order to obtain maximal health benefits.
• All men should undergo testing of blood vitamin D levels and follow their primary health care provider recommendations with regard to vitamin D supplementation.   

• All men should undergo testing for the 5 components of MetSyn listed above, and follow their primary health care provider recommendations with regard to necessary lifestyle changes and/or medication use.
    

Reference

Farrell SW, Leonard D, Barlow CE, Willis BL, Pavlovic A, DeFina LF, Haskell WL. Cardiorespiratory Fitness, Serum Vitamin D, and Prevalence of Metabolic Syndrome in Men. Med Sci Sports Exerc. 2020 Jul 16. doi: 10.1249/MSS.0000000000002445. Online ahead of print. PMID: 32694363