Insulin Resistance in Middle Aged Normotensive Offspring of the Hypertensive Parents in Korea

BACKGROUND: The insulin resistance is common in the patients with essential hypertension, even in the absence of non-insulin-dependent diabetes mellitus(NIDDM) or hyperlipidemia. It is well known that the offspring of patients with NIDDM have shown less insulin sensitivity compared with that of normal parents. But it is not yet known whether the insulin resistance is common in the offspring of patients with essential hypertension in Korea, who have no hypertension, NIDDM and hyperlipidemia. The aims of this study were to find out whether the insulin resistance exist in the middle aged normal offspring of the patients with essential hypertension and whether the insulin resistance is dependent on the metabolic abnormalities such as the body mass index(BMI), obesity and hyperlipidemia. METHODS: The serum lipid profiles and oral glucose tolerance test were performed. The anthropometrical measurement was done. The abdominal CT scan at umbilicus level and thigh CT was performed in the 11 offspring of parents with essential hypertension(group I;male : 7, female : 4)and 24 offspring of parents without essential hypertension, NIDDM, ischemic heart disease and hyperlipidemia(group II; male : 9, female : 15). RESULTS: The average age of group I was 44.1+/-6.9 years, and that of the group II was 47.5+/-9.5 years. There were no significant differences in the blood pressure, weight, BMI, waist to hip ratio, waist to thigh ratio. And there were no significant differences in the serum cholesterol, triglyceride, HDL-cholesterol, serum Na, and plasma renin activities between both groups. Fasting plasma insulin and 2 hour insulin after 75gm glucose ingestion were significantly higher in group I than in group II(8.5+/-3.0mU/mL versus 5.0+/-1.8mU/mL, 61.6+/-31.7mU/mL versus 33.3+/-16.8mU/mL, p<0.05). The insulin sensitivity index was significantly lower in group I than in group II(355.1+/-92.6 versus 451.8+/-88.1, p<0.05). The visceral fat area was wider in group I than in group II(102.0+/-30.7cm2 versus 64.5+/-28.5cm2, p<0.05). The multiple regression analysis with the fasting plasma insulin and insulin sensitivity index as the dependent variables and family history of essential hypertension, visceral fat area and BMI as the predictor variables revealed that only the family history was associated with the fasting plasma insulin and insulin sensitivity index. CONCLUSIONS: The offspring of the parents with essential hypertension showed the insulin resistance with increased visceral fat area in comparison with the offspring of the parents without essential hypertension.

Insulin Resistance as an Associated Factor of Essential Hypertension in Korean

BACKGROUND: The insulin resistance is reported as the independent risk factor of the DM and the ischemic heart disease. The association between the insulin resistance and the essential hypertension was reported at the various countries and races. We performed this study to know if the hypertensive patients show the increased insulin resistance than that of the normotensive persons and factors that influence the insulin resistance and the blood pressure. METHODS: The serum lipid profiles, OGTT, body habitus measurement and abdominal CT at umbilical level were performed in 24 hypertensive patients(male : 10, female : 14) and 45 normotensive persons(male : 19, female : 26) who showed the same distributions of age, sex, weight and body mass index(BMI). RESULTS: The average age of the hypertensive group was 49.1+/-7.9 years, and that of the normotensive group was 46.1+/-7.6 years(p>0.05). The average blood pressure of the hypertensive group was 152.2+/-14.2/98.4+/-6.4mmHg and that of the normotensive group was 116.8+/-9.4/78.2+/-49.mmHg(p<0.001). The hypertensive group had significantly higher area under curve(AUC) of glucose(246.8+/-30.4 Vs 219.2+/-32.2mg/dL.hr) and AUC of insulin(88.9+/-38.2 Vs 69.6+/-34.2microU/mL.hr) than the normotensive group(p<0.05), while there were no differences in the age, sex, weight, body mass index(BMI) and waist to hip ratio(WHR) between two groups. They had nodifferences in lipid profile and plasma renin activity. In CT assessment, the hypertensive group had significantly higher visceral fat to thigh muscle area ratio(VSFTM ratio)(0.61+/-0.29 Vs 0.47+/-0.20) and visceral fat to thigh muscle and fat area ratio(VSFTMF ratio)(0.27+/-0.10 Vs 0.22+/-0.13)(p<0.05), while they had same degree of visceral fat to subcutaneous fat area(VS) ratio and visceral fat area. The visceral fat area, VSFTM ratio, VS ratio, visceral fat area to thigh fat area ratio(VSFTF ratio) were positively correlated with AUC of insulin and AUC of glucose ordinary(p<0.05). After adjustment for plasma insulin, AUC of insulin, VS ratio, VSFTM ratio, age and BMI, the AUC of glucose was positively correlated with the diastolic blood pressure(R square=0.19, p <0.05) and the AUC of glucose and WTR were positively correlated with the systolic blood pressure(R square=0.26, p<0.05). THe subgroup over the 75 percentile of AUC of glucose, AUC of insulin and VSFTM ratio in study population had significantly higher odds ratio of the hypertension(OR of AUC of glusose : 5.8, OR of AUC of insulin : 3.2, OR of VSFTM ratio : 4.5, p<0.05). CONCLUSION: These results suggest that the insulin resistance is more prevalent in the hypertensive patients and associated with the hypertension.