Metabolic syndrome, also known as "Syndrome X", is a combination of medical disorders that increases the risk of heart disease and diabetes.

The symptoms include:

• High blood pressure
• High blood sugar levels
• High levels of triglycerides
• Low levels of HDL
• Excess fat around your waist

Some studies estimate the prevalence in the USA to be up to 25% of the population.

References

http://www.nlm.nih.gov/medlineplus/metabolicsyndrome.html; Ford ES, Giles WH, Dietz WH (2002). Prevalence of metabolic syndrome among US adults: findings from the third National Health and Nutrition Examination Survey. JAMA 287(3):356-359. PMID 11790215