Metabolic Syndrome Predicted Type 2 Diabetes in Japanese

The presence of metabolic syndrome significantly increased the risk of incident type 2 diabetes independent of impaired fasting glucose, researchers studying a Japanese population have found.

The finding suggests that metabolic syndrome can be used to identify persons at high risk for developing the disease, they said.

The study adds to a body of data showing mixed results for the value of metabolic syndrome as a predictor of type 2 diabetes. One cohort study showed it to be superior to simple impaired fasting glucose alone, while others have found metabolic syndrome to be comparable or inferior to IFG alone. Further, most previous studies were performed in Western populations; the present study adds information in an Asian cohort (Diabetes Care 2009 Sept. 3 [doi:10.2337/dc09-0896

Led by Dr. Naoko Mukai and associates at Kyushu University, Fukuoka, Japan, the study comprised 1,935 nondiabetic subjects aged 40–79 years who were enrolled in an ongoing population-based study of cardiovascular disease and its risk factors between 1988 and November 2002 in the town of Hisayama on Kyushu Island. The subjects were followed up prospectively for a mean of 11.8 years. At baseline and during regular examinations, the subjects underwent a fasting oral glucose tolerance test.

During follow-up, 286 subjects (145 men and 141 women) developed diabetes. Compared with those who did not have metabolic syndrome, the multivariate-adjusted risk for incident diabetes was significantly higher in subjects with metabolic syndrome in both sexes, even after adjustment for confounding factors that included age, family history of diabetes, total cholesterol, alcohol intake, smoking habits, and regular exercise. Hazard ratios were 2.58 for men and 3.69 for women.

Among the individual components of metabolic syndrome, impaired fasting glucose was the strongest predictor of diabetes in both sexes, raising the risk more than threefold.

In normal fasting glucose subjects, risk increased significantly according to number of metabolic syndrome components. Metabolic syndrome defined without the fasting plasma glucose component was also a significant risk factor.

To the authors' knowledge, this is the first report indicating that metabolic syndrome is associated with future diabetes for both sexes in a general Japanese population.

The authors mentioned two possible study limitations, the first being that metabolic syndrome diagnosis was based on a “a single measurement of its components at baseline. … The risk factor levels might have changed during the follow-up due to modifications in lifestyle or medication.” Also, data on antilipidemic medication use was not included in the study.

However, the researchers wrote: “These biases have the potential to underestimate the association between [metabolic syndrome] and incident [type 2 diabetes], and thus the true impact of [metabolic syndrome] on the occurrence of [type 2 diabetes] may be stronger than that shown in our findings.”

The authors said they had no relevant conflicts of interest.

The presence of metabolic syndrome significantly increased the risk of incident type 2 diabetes independent of impaired fasting glucose, researchers studying a Japanese population have found.

The finding suggests that metabolic syndrome can be used to identify persons at high risk for developing the disease, they said.

The study adds to a body of data showing mixed results for the value of metabolic syndrome as a predictor of type 2 diabetes. One cohort study showed it to be superior to simple impaired fasting glucose alone, while others have found metabolic syndrome to be comparable or inferior to IFG alone. Further, most previous studies were performed in Western populations; the present study adds information in an Asian cohort (Diabetes Care 2009 Sept. 3 [doi:10.2337/dc09-0896

Led by Dr. Naoko Mukai and associates at Kyushu University, Fukuoka, Japan, the study comprised 1,935 nondiabetic subjects aged 40–79 years who were enrolled in an ongoing population-based study of cardiovascular disease and its risk factors between 1988 and November 2002 in the town of Hisayama on Kyushu Island. The subjects were followed up prospectively for a mean of 11.8 years. At baseline and during regular examinations, the subjects underwent a fasting oral glucose tolerance test.

During follow-up, 286 subjects (145 men and 141 women) developed diabetes. Compared with those who did not have metabolic syndrome, the multivariate-adjusted risk for incident diabetes was significantly higher in subjects with metabolic syndrome in both sexes, even after adjustment for confounding factors that included age, family history of diabetes, total cholesterol, alcohol intake, smoking habits, and regular exercise. Hazard ratios were 2.58 for men and 3.69 for women.

Among the individual components of metabolic syndrome, impaired fasting glucose was the strongest predictor of diabetes in both sexes, raising the risk more than threefold.

In normal fasting glucose subjects, risk increased significantly according to number of metabolic syndrome components. Metabolic syndrome defined without the fasting plasma glucose component was also a significant risk factor.

To the authors' knowledge, this is the first report indicating that metabolic syndrome is associated with future diabetes for both sexes in a general Japanese population.

The authors mentioned two possible study limitations, the first being that metabolic syndrome diagnosis was based on a “a single measurement of its components at baseline. … The risk factor levels might have changed during the follow-up due to modifications in lifestyle or medication.” Also, data on antilipidemic medication use was not included in the study.

However, the researchers wrote: “These biases have the potential to underestimate the association between [metabolic syndrome] and incident [type 2 diabetes], and thus the true impact of [metabolic syndrome] on the occurrence of [type 2 diabetes] may be stronger than that shown in our findings.”

The authors said they had no relevant conflicts of interest.

The presence of metabolic syndrome significantly increased the risk of incident type 2 diabetes independent of impaired fasting glucose, researchers studying a Japanese population have found.

The finding suggests that metabolic syndrome can be used to identify persons at high risk for developing the disease, they said.

The study adds to a body of data showing mixed results for the value of metabolic syndrome as a predictor of type 2 diabetes. One cohort study showed it to be superior to simple impaired fasting glucose alone, while others have found metabolic syndrome to be comparable or inferior to IFG alone. Further, most previous studies were performed in Western populations; the present study adds information in an Asian cohort (Diabetes Care 2009 Sept. 3 [doi:10.2337/dc09-0896

Led by Dr. Naoko Mukai and associates at Kyushu University, Fukuoka, Japan, the study comprised 1,935 nondiabetic subjects aged 40–79 years who were enrolled in an ongoing population-based study of cardiovascular disease and its risk factors between 1988 and November 2002 in the town of Hisayama on Kyushu Island. The subjects were followed up prospectively for a mean of 11.8 years. At baseline and during regular examinations, the subjects underwent a fasting oral glucose tolerance test.

During follow-up, 286 subjects (145 men and 141 women) developed diabetes. Compared with those who did not have metabolic syndrome, the multivariate-adjusted risk for incident diabetes was significantly higher in subjects with metabolic syndrome in both sexes, even after adjustment for confounding factors that included age, family history of diabetes, total cholesterol, alcohol intake, smoking habits, and regular exercise. Hazard ratios were 2.58 for men and 3.69 for women.

Among the individual components of metabolic syndrome, impaired fasting glucose was the strongest predictor of diabetes in both sexes, raising the risk more than threefold.

In normal fasting glucose subjects, risk increased significantly according to number of metabolic syndrome components. Metabolic syndrome defined without the fasting plasma glucose component was also a significant risk factor.

To the authors' knowledge, this is the first report indicating that metabolic syndrome is associated with future diabetes for both sexes in a general Japanese population.

The authors mentioned two possible study limitations, the first being that metabolic syndrome diagnosis was based on a “a single measurement of its components at baseline. … The risk factor levels might have changed during the follow-up due to modifications in lifestyle or medication.” Also, data on antilipidemic medication use was not included in the study.

However, the researchers wrote: “These biases have the potential to underestimate the association between [metabolic syndrome] and incident [type 2 diabetes], and thus the true impact of [metabolic syndrome] on the occurrence of [type 2 diabetes] may be stronger than that shown in our findings.”

The authors said they had no relevant conflicts of interest.