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Syndrome X: is it for real?
1Department of Human Genetics, University of Michigan Medical School, Ann Arbor, USA.
Genetic Epidemiology
|April 2, 1998
Summary
Syndrome X, the cluster of hypertension, non-insulin-dependent diabetes mellitus (NIDDM), and obesity, lacks a unifying cause. The association is driven by body mass index (BMI) and hypertension, not a distinct syndrome. Genetic factors were also considered.
Area of Science:
- Epidemiology
- Metabolic Syndrome Research
- Genetics
Background:
- Syndrome X, also known as metabolic syndrome, describes a cluster of conditions including hypertension, non-insulin-dependent diabetes mellitus (NIDDM), obesity, insulin resistance, and dyslipidemia.
- The concept of Syndrome X posits a single underlying pathophysiology unifying these interrelated metabolic and cardiovascular risk factors.
- Previous research has suggested a syndrome-like association, but the validity of a unifying pathophysiology requires further investigation in diverse populations.
Purpose of the Study:
- To investigate the validity of Syndrome X as a distinct entity with a unifying pathophysiology.
- To analyze the associations between hypertension, non-insulin-dependent diabetes mellitus (NIDDM), and body mass index (BMI) in population samples.
- To explore potential genetic influences on the observed trait associations.
Main Methods:
- Population-based samples from Tecumseh, Michigan, and Hiroshima, Japan, including individuals aged 40 years and older.
- Analysis of hypertension, NIDDM, and BMI using chi-squared tests and log-linear models.
- Stratification by age (≥40, ≥50 years) and obesity (BMI ≥27, ≥30) to assess interactions.
Main Results:
- Non-random associations were found between hypertension, NIDDM, and BMI, with an excess of individuals exhibiting all three traits.
- Log-linear analyses revealed no significant three-factor interaction (Syndrome X), indicating a lack of a unifying pathophysiology.
- A significant two-factor interaction was observed between BMI and hypertension, suggesting this pair drives the observed associations.
Conclusions:
- The data do not support the existence of Syndrome X as a distinct entity with a single unifying cause.
- The observed association between hypertension, NIDDM, and BMI is primarily driven by the interaction between BMI and hypertension.
- Further research is needed to elucidate the complex interplay of genetic and environmental factors contributing to these metabolic and cardiovascular risk factors.
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