[The optimal cutoff value of waist-to-height ratio in Chinese: based on cardiovascular risk and metabolic disease]

Factors Associated with the 4-Year Estimated Incidence of Type 2 Diabetes Mellitus by Sex in Korean Adults: Secondary Data Analysis

It is important to prevent the increase in the prevalence of diabetes mellitus (DM) worldwide by efficiently managing its controllable risk factors. This study aimed to identify factors associated with the 4-year estimated incidence of type 2 DM (T2DM) by sex and provide basic data for a sex-specific strategic approach to lifestyle modification. We performed a secondary data analysis using raw data from the seventh Korea National Health and Nutrition Examination Survey (KNHANES, 2016-2018). The KNHANES is a descriptive correlational survey designed to examine sex differences in the factors associated with the 4-year estimated incidence of T2DM. This study included 9,614 Korean adults (4,134 men and 5,480 women) aged 40-69 years without a diagnosis of T2DM. For the statistical analysis, a complex sample analysis was performed for sex comparison using the χ ²-test or one-way analysis of variance; a multiple regression analysis was performed to analyze the sex-specific influencing variables of 4-year estimated T2DM incidence. The waist-to-height ratio, an indicator of central obesity in adults, showed the strongest association with the 4-year estimated incidence of T2DM in both groups (male: β = 0.33, p ≤ 0.001; female: β = 0.38, p ≤ 0.001). The influencing variables were the monthly drinking rate (β = 0.07, p ≤ 0.001) and sleep time (β = -0.03, p < 0.05) in men and the sedentary time in women (β = 0.03, p < 0.05). The overall explanatory power of these variables was 11.3% for men and 14.3% for women. Thus, significant sex differences were found in the 4-year estimated incidence of T2DM. Therefore, intervention programs need to be sex-specific to enhance the efficacy of the interventions in reducing the incidence of T2DM, and such intervention programs should be administered with a strategic approach differentiated by sex.

Association between obstructive sleep apnea syndrome and waist-to-height ratio

PURPOSE

Obesity is among the known risk factors for obstructive sleep apnea syndrome (OSAS). In this study, our aim was to investigate the correlation of waist-to-height ratio, an indicator of central obesity, with presence and severity of OSAS; to compare the use of this ratio with the use of waist circumference and body mass index (BMI); and to determine OSAS-related cutoff values.

METHODS

The patient records were retrospectively analyzed for whom a polysomnography was conducted at our sleep. Sex, age, Apnea-Hypopnea Index (AHI), waist circumference, height, and BMI values of those patients were recorded. AHI scores were used to classify severity of OSAS.

RESULTS

The study included 437 OSAS patients and 72 control cases. Out of the patient group, OSAS was severe in 208 (47%) patients, moderate in 124 (28%), and mild in 105 (24%) of them. In the group of OSAS patients, waist-to-height ratio, waist circumference, and BMI were higher compared to the control group with a further difference of all three parameters among severe, moderate, mild OSAS, and controls both in males and females. Cutoff values for OSAS of females were 95.5 cm for waist circumference, 0.595 for waist-to-height ratio, and 27.75 for BMI whereas the cutoff values of males were 100.5 cm, 0.575, and 27.75, respectively.

CONCLUSIONS

A high value of waist circumference, waist-to-height ratio, and BMI is associated with the presence and severity of OSAS. We have determined the cutoff values of the studied anthropometric measurements in both sexes for OSAS and severe OSAS.