We administered a series of community-based health surveys among Chiayi County’s elder individuals from 2017 to 2019. Those who were above 65 years old and have lived in Chiayi County for more than one year were invited to participate in the surveys. The inclusion criteria were individuals 65 to 85 years old who were free from any infectious disease or acute disorders in the past three weeks preceding the start of the surveys.
General demographic data including gender, age, residency, education level, occupation, and the need for a caregiver were collected using a standard questionnaire. History of chronic diseases including DM, hypertension, cardiovascular disease, chronic kidney disease, any type of cancer, and cerebrovascular disease as well as medication history were recorded by research technician. Lifestyle patterns such as dietary habits, cigarette smoking, alcohol intake, and daily activity were also collected from the study participants.
The anthropometric characteristics including body weight (BW), height, waist circumference (WC), hip circumference (HIP), and body fat (BFAT) were measured using standard methods. The height was measured in meters using a digital stadiometer that recorded to the nearest 0.5 cm and the subjects were barefoot and wore only light indoor clothing. BW was measured to an accuracy of 0.1 kg using a standard beam balance scale. The BFAT was obtained using a segmental body composition analyzer (TBF-410, Tanita Corp., Tokyo, Japan) and was expressed as percentages. The WC and HIP were measured using standard methods suggested by the WHO (World Health Organization). The WC was measured to the nearest 0.1 cm at the midpoint between the margin of the last rib and the iliac crest of the ilium. The HIP was measured to the widest diameter of the pelvic region. We calculated the body mass index (BMI) as BW (kg) divided by the square of the height (m2), while the waist-to-hip ratio was calculated by WC (cm) divided by the HIP (cm).
Grip strength measurement
The GS was measured using digital dynamometers (TKK5101). All subjects were in a seated position while fully extending their elbows. After two to three minutes of rest, we measured the GS on either the right or left hand for two times. Two values for the GS were recorded, and the mean value of the two recordings was used for analysis18. The subjects were divided into four subgroups according to their BW classification and GS. Non-obese (OB-) subjects were defined as those with a BMI < 27, while obese (OB+) individuals were defined as those with a BMI ≥ 27. A normal grip strength (GS+) was defined as GS ≥ 30kg in males and GS ≥ 20 kg in females, and a weak GS (GS-) was defined as GS ≤ 30 kg in males and GS ≤ 20 kg in females3.
Blood pressure measurement
Blood pressure was obtained after the subjects had rested for five to ten minutes. In a seated position, the subjects’ arms were positioned at the same height as the heart and inserted into cuffs of appropriate sizes. Two measurements were recorded, and the mean value of the two recordings was used for data analysis.
Blood specimen collection
After 10–12 hours of overnight fasting, 10 ml of venous blood was collected from the subjects using a venous container. The plasma and serum were separated from the blood within one hour and stored at − 80°C until analysis.
Plasma glucose and lipid profile measurement
The plasma glucose concentration of each subject was analyzed immediately after blood sampling and was determined by the glucose oxidase method using the Beckman Glucose Analyzer II (Beckman Instruments, Fullerton, CA)19. We measured the total cholesterol (CHOL) level using an esterase oxidase method20 and the triglyceride (TG) level using an enzymatic procedure21 using a Hitachi 7150 auto-analyzer (Hitachi, Tokyo, Japan). Levels of high-density lipoprotein (HDLC) and low-density lipoprotein (LDLC) were measured using an enzymatic method22.
Approval of the IRB
All participants provided written informed consent and agreed to have their general demographic data, questionnaire, anthropometric data, and blood samples taken for this study. The institutional review board of the Tri-Service General Hospital approved this study (Number: TSGHIRB-1-108-05-073).
We used SPSS ver. 22 to conduct all statistical analyses. Continuous variables, such as anthropometric measures, grip strength, and cardiometabolic risk profile, were presented as sample mean and SD. The student’s t-test was used to compare the differences between the groups. The analysis of variance (ANOVA) test was used to compare more than three groups. The categorical variables were described as numbers and percentages. The chi-square test was used to compare the differences among two or more groups. We used multivariate regression analyses and logistic regression analyses for further statistical inference. A two-tailed p value less than 0.05 was considered statistically significant.