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Older adults were enrolled in the HABCS conducted in 2017–2018. We excluded 47 participants younger than 65 years, 36 participants with missing Mini-Mental State Examination (MMSE) scores, 51 participants with missing calf circumference data, and 311 participants with missing handgrip strength data. Based on U±2.58σ (Supplementary Figure S1 available in www.besjournal.com), outlier data for handgrip strength (≥ 46 kg, 36 participants) and outlier data for calf circumference (≤ 18 cm or ≥ 44 cm, 10 participants) were also excluded. The final study sample included 2,525 older adults (Figure 1). This study obtained informed consent of all participants or their relatives and was approved by the Biomedical Ethics Committee of Peking University, Beijing, China (IRB00001052-13074).
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The Mini-Mental State Examination (MMSE) questionnaire, which was translated into Chinese based on the internationally standard MMSE questionnaire, was used to assess cognitive impairment. There were 5 aspects of the MMSE questionnaire, including orientation, registration, attention and calculation, recall, and language[25]. Supplementary Table S1 (available in www.besjournal.com) shows the specific questions of the 5 components and their point values. For example, “Orientation” contains the questions, “What is the (year) (season) (date) (day) (month)?” and “Where are we: (state) (county) (town) (hospital) (floor)?”. The total score is between 0 and 30; the higher the score, the greater the cognitive function. When the score was less than 24 (score: 0–23), participants were considered to have cognitive impairment[26,27]. The informed consent statement suggested relatives could provide consent, so proxy respondents were available to participate.
Components Question Score Orientation What is the (year) (season) (date) (day) (month)? 5 Where are we: (state) (county) (town) (hospital) (floor)? 5 Registration Name 3 objects ("table", "apple", "clothes" ): 1 second to say each. Then ask the patient all 3 after you have said them. Give 1 point for each correct answer. Then repeat them until he learns all 3. Count trials and record. 3 Attention and Calculation Serial 7’s. 1 point for each correct. Stop after 5 answers.
$20-$3=?
$20-$3-$3=?
$20-$3-$3-$3=?
$20-$3-$3-$3-$3=?
$20-$3-$3-$3-$3-$3=?5 Recall Ask for the 3 objects repeated above. Give 1 point for each correct. 3 Language Name a pencil, and watch (2 points) 9 Repeat the following “As a man sows, so he shall reap” (1 point) Follow a 3-stage command: “Take a paper in your right hand, fold it in half, and put it on the floor” (3 points) Read and obey the following:
CLOSE YOUR EYES (1 point)
Write a sentence (1 point)
Copy design (1 point)Table S1. Components of the mini-mental state examination (MMSE)
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The formula for determining sarcopenia contains three indicators: age, handgrip strength, and calf circumference, which was created by Ishii et al.[28]. A Jamar J00105 hydraulic hand dynamometer was used to measure handgrip strength in a sitting position. The elbow was placed against the side of the body and bent to a 90 angle with the forearm holding the dynamometer’s armrest. Handgrip strength was assessed using the mean of the right hand and left hand values, expressed as kg[29,30]. The participants' calf circumference was measured in a supine or sitting position. The calf was at right angles to the thigh, and the measurement was made at the maximum circumference of the non-dominant leg[31, 32]. The formulas for determining sarcopenia were different depending on gender. Table 1 for the specific formula[28].
Gender Formula Female 0.80 × (age − 64) −5.09 × (grip strength − 34) − 3.28 × (calf circumference − 42) Male 0.62 × (age − 64) − 3.09 × (grip strength − 50) − 4.64 × (calf circumference − 42) Table 1. The formula for determining sarcopenia
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The covariates included in our models were collected using a structured HABCS questionnaire and were as follows: 1) Sociodemographic characteristics, including age, gender, nationality, marital status, and educational attainment. 2) Lifestyle behaviors, including smoking, drinking, and physical activity. 3) Health characteristics, including body mass index (BMI), hypertension, diabetes, self-reported heart disease, and self-reported respiratory diseases.
Age and educational attainment were modeled as continuous variables (in years). Gender was defined as male or female. Nationality was determined as Han Chinese or a minority. Regular exercise was classified as “yes” or “no”, based on the answer to the following question, “Do you often participate in physical activities, including walking, playing ball, running, and Qigong?”. Smoking and drinking were also classified as “yes” or “no”[27]. BMI was divided into 4 categories according to the guidelines for Chinese individuals: underweight (BMI < 18.5 kg/m2), normal weight (BMI 18.5 to < 24.0 kg/m2), overweight (BMI 24.0 to < 28.0 kg/m2), and obese (BMI higher than or equal to 28.0 kg/m2)[33]. The interviewer took blood pressure twice for older adults, at least two minutes apart. Hypertension was defined as diastolic blood pressure ≥ 90 mmHg or systolic blood pressure ≥ 140 mmHg, or self-reported hypertension[34]. Blood specimens were obtained after at least an 8-h fasting period. Venous blood samples were centrifuged at 4 °C, and serum was separated directly and stored at −80 °C until clinical biochemistry analysis. Diabetes was defined as fasting blood glucose ≥ 7.0 mmol/L or self-reported diabetes[35]. Heart disease was defined as self-reported heart disease (yes, no). Respiratory disease was defined as self-reported bronchitis, emphysema, asthma or pneumonia (yes, no).
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Categorical variables were presented as numbers and percentages. Chi-square tests were used to compare differences in baseline sociodemographic characteristics, lifestyle behaviors, and health characteristics between the sarcopenic and non-sarcopenic groups. Before conducting the analysis, we tested the normality of the continuous variables. Data with normal distributions were presented as means and standard deviations. T-tests or analysis of variance for parametric continuous variables were performed to compare differences between the sarcopenic and non-sarcopenic groups. Data not normally distributed were presented as median [Inter Quartile Range (IQR)], and Kruskal-Wallis for non-parametric continuous variables was used to compare differences between groups. Multiple logistic regression models were used to assess the associations of sarcopenia, handgrip strength, handgrip strength quartile, calf circumference and calf circumference quartile with cognitive impairment. Odds ratios (ORs) with 95% confidence intervals (CIs) were calculated from the logistic regression models to represent the effect estimations. We also estimated the associations of sarcopenia, handgrip strength, handgrip strength quartile, calf circumference and calf circumference quartile with MMSE score by multiple linear regression. To evaluate the dose-response associations of handgrip strength and calf circumference with cognitive impairment, we used the restricted cubic spline (RCS) function with three knots located at the 5th, 50th, and 95th percentiles of handgrip strength and calf circumference. The effects were represented by the OR and 95% CIs for cognitive impairment, where the reference value for calf circumference was 19 cm and where the reference value for handgrip strength was 0 kg.
We performed a stratified analysis to estimate potentially modifiable effects by age (< 80 vs. ≥ 80 years), gender (male vs. female), regular exercise (yes vs. no), smoking (yes vs. no), drinking (yes vs. no), BMI (≥ 24 vs. < 24), diabetes (yes vs. no), hypertension (yes vs. no). We assessed potential modifiable effects by modeling the cross-product term of the stratifying variable with sarcopenia. In order to test the robustness of the results, we performed some sensitivity analyses. First, to minimize the influence of reverse causation, we conducted a sensitivity analysis by excluding participants with major chronic diseases (hypertension, diabetes, heart disease, and respiratory diseases). Second, we used the maximum grip strength value of the dominant hand to explore the association of grip strength with cognitive impairment. Moreover, we did not exclude the outliers of grip strength and calf circumference. In addition, the frequencies of vegetable, egg, meat, and fish consumption (almost every day, at least once a week, at least once a month, sometimes, or rarely) were added to model 2. Finally, dyslipidemia was added to model 3.
All statistical analyses were performed using SAS version 9.4 (SAS Institute, Inc., Cary, NC, USA). We used the ggBaseline2 macro program to determine the basic characteristic differences. In this process, two programs, PROC MEANS and PROC FREQ were applied. In the multiple logistic regression analysis, the PROC LOGISTIC procedure was used. The PROC REG procedure was used in multiple linear regression analysis. Additionally, the %RCS_REG macro program was used to draw RCS curves. P values less than 0.05 of a two-sided test were considered statistically significant for all analyses.
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Table 2 shows the participants’ characteristics. Age, educational attainment, handgrip strength and calf circumference were skewed, and therefore we used the Mann-Whitney U nonparametric test for these data. The mean age was 84.5 years among the 2,525 participants, with median (IQR) age of 84 (75–93) years. The median (IQR) handgrip strength was 16.8 (10.0–24.0) kg. The median (IQR) calf circumference was 31 (28–34) cm. And 47.8% were women, 17.2% were smokers, and 17.6% were alcohol drinkers. The prevalence of cognitive impairment was 34.6% among all participants, 40.0% among participants with sarcopenia, and 12.2% among participants without sarcopenia. Hypertension was the most prevalent chronic diseases (70.1%). Compared with the non-sarcopenic group, participants in the sarcopenic group were older, had lower handgrip strength and calf circumference, as well as fewer years of education. Participants in the sarcopenic group had a higher prevalence of cognitive impairment (P < 0.001). Supplementary Table S2 (available in www.besjournal.com) shows the characteristics of participants with 95% CIs for continuous variables and percentages as well as 95% CIs for the percentages.
Variables Total Sarcopenic Non-sarcopenic P value (N = 2,525) (N = 2,032) (N = 493) Age (years) < 0.001 Mean ± SD 84.5 ± 11.3 87.2 ± 10.5 73.3 ± 6.3 Median (IQR) 84 (75–93 ) 87 (79–95 ) 72 (69–76) Handgrip strength < 0.001 Mean ± SD 17.6 ± 9.5 14.9 ± 7.9 28.5 ± 7.5 Median (IQR) 16.8 (10.0–24.0) 14.0 (8.8–20.3) 28.3 (21.5–34.7) Calf circumference < 0.001 Mean ± SD 30.6 ± 4.4 29.6 ± 4.0 34.7 ± 3.2 Median (IQR) 31.0 (28–34) 30 (27–32) 35.0 (33–37) Education attainment (years) < 0.001 Mean ± SD 2.7 ± 3.4 2.1 ± 3.1 4.9 ± 3.6 Median (IQR) 0 (0–5) 0 (0–4) 6 (2–7) Cognitive impairment (%) < 0.001 Yes 873 (34.6) 813 (40.0) 60 (12.2) No 1,652 (65.4) 1,219 (60.0) 433 (87.8) Nationality 0.371 Han 2,310 (91.5) 1,854 (91.2) 456 (92.5) Minority 215 (8.5) 178 (8.8) 37 (7.5) Gender (%) 0.391 Male 2,503 (99.1) 2,015 (99.2) 488 (99) Female 22 (0.9) 17 (0.8) 5 (1.0) Current marital status (%) < 0.001 Married 2,503 (99.1) 2,015 (99.2) 488 (99) Unmarried 22 (0.9) 17 (0.8) 5 (1.0) Smoking (%) 0.134 Yes 434 (17.2) 338 (16.6) 96 (19.5) No 2,091 (82.8) 1,694 (83.4) 397 (80.5) Alcohol consumption (%) 0.002 Yes 445 (17.6) 334 (16.4) 111 (22.5) No 2,080 (82.4) 1,698 (83.6) 382 (77.5) Regular exercise (%) < 0.001 Yes 515 (20.4) 359 (17.7) 156 (31.6) No 2,010 (79.6) 1,673 (82.3) 337 (68.4) BMI (kg/m2) < 0.001 < 18.5 371 (14.7) 359 (17.7) 12 (2.4) 18.5–23.9 1,347 (53.3) 1,160 (57.1) 187 (37.9) 24.0–27.9 609 (24.1) 396 (19.5) 213 (43.2) ≥ 28.0 198 (7.8) 117 (5.8) 81 (16.4) Hypertension (%) 0.008 Yes 1,771 (70.1) 1,401 (68.9) 370 (75.1) No 754 (29.9) 631 (31.1) 123 (24.9) Diabetes (%) 0.315 Yes 334 (13.2) 262 (12.9) 72 (14.6) No 2,191 (86.8) 1,770 (87.1) 421 (85.4) Heart disease (%) 0.355 Yes 268 (10.6) 210 (10.3) 58 (11.8) No 2,257 (89.4) 1,822 (89.7) 435 (88.2) Respiratory diseases (%) 0.063 Yes 217 (8.6) 185 (9.1) 32 (6.5) No 2,308 (91.4) 1,847 (90.9) 461 (93.5) Note. BMI: body mass index. Table 2. Characteristics of participants according to sarcopenia status
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Sarcopenia (based on the formula derived by Ishii) was positively associated with cognitive impairment (Table 3). Compared with participants without sarcopenia, the crude OR for cognitive impairment was 4.81 (95% CI: 3.62–6.40; P < 0.001) among participants with sarcopenia. The fully adjusted model (model 3) still showed a statistically significant positive association (OR = 2.55, 95% CI: 1.86–3.50; P < 0.001). Handgrip strength and calf circumference were negatively associated with cognitive impairment (Table 3). Compared with individuals in the first quartile (Q1) of calf circumference, the adjusted ORs in the second, third, and fourth quartiles (Q2, Q3 and Q4) were 0.75 (95% CI: 0.58–0.96; P = 0.025), 0.59 (95% CI: 0.44–0.79; P < 0.001), and 0.62 (95% CI: 0.45–0.86; P = 0.004), respectively. Compared with individuals in Q1 of handgrip strength, the adjusted ORs in Q2, Q3, and Q4 were 0.49 (95% CI: 0.38–0.62; P < 0.001), 0.31 (95% CI: 0.23–0.41; P < 0.001), and 0.30 (95% CI: 0.21–0.44; P < 0.001), respectively.
Independent variables Crude Model Model 1 Model 2 Model 3 OR (95% CI) P value OR (95% CI) P value OR (95% CI) P value OR (95% CI) P value Sarcopenia No 1.00 [Reference] 1.00 [Reference] 1.00 [Reference] 1.00 [Reference] Yes 4.81 (3.62−6.40) < 0.001 2.73 (2.00−3.71) < 0.001 2.72 (1.99−3.70) < 0.001 2.55 (1.86−3.50) < 0.001 Calf circumference (cm) 0.86 (0.85−0.88) < 0.001 0.96 (0.93−0.98) < 0.001 0.96 (0.93−0.98) < 0.001 0.95 (0.93−0.98) 0.001 Calf circumference quartile Q1 (n = 584, 19−27 cm) 1.00 [Reference] 1.00 [Reference] 1.00 [Reference] 1.00 [Reference] Q2 (n = 667, 28−30 cm) 0.46 (0.37−0.58) < 0.001 0.75 (0.58−0.96) 0.023 0.74 (0.58−0.96) 0.023 0.75 (0.58−0.96) 0.025 Q3 (n = 638, 31−33 cm) 0.25 (0.19−0.31) < 0.001 0.59 (0.45−0.78) < 0.001 0.59 (0.45−0.79) 0.000 0.59 (0.44−0.79) < 0.001 Q4 (n = 636, 34−43 cm) 0.19 (0.15−0.25) < 0.001 0.64 (0.48−0.87) 0.004 0.64 (0.47−0.87) 0.004 0.62 (0.45−0.86) 0.004 Handgrip strength (kg) 0.89 (0.88−0.90) < 0.001 0.94 (0.93−0.96) < 0.001 0.94 (0.93−0.96) < 0.001 0.94 (0.93−0.96) < 0.001 Handgrip strength quartile Q1 (n = 612, 0.0−9.8 kg) 1.00 [Reference] 1.00 [Reference] 1.00 [Reference] 1.00 [Reference] Q2 (n = 660, 10.0−16.8 kg) 0.35 (0.28−0.44) < 0.001 0.50 (0.39−0.63) < 0.001 0.49 (0.38−0.62) < 0.001 0.49 (0.38−0.62) < 0.001 Q3 (n = 635, 17.0−24.3 kg) 0.13 (0.10−0.17) < 0.001 0.32 (0.23−0.43) < 0.001 0.31 (0.23−0.42) < 0.001 0.31 (0.23−0.41) < 0.001 Q4 (n = 618, 24.5−45.8 kg) 0.07 (0.05−0.10) < 0.001 0.32 (0.22−0.46) < 0.001 0.31 (0.21−0.45) < 0.001 0.30 (0.21−0.44) < 0.001 Note. Handgrip strength was calcaulated by the mean of right and left hand; OR, odds ratio; CI, confidence interval; Model 1: Multivariate logistic analysis was performed after adjusting for age, gender, nationality, education attainment, and marital status. Model 2 was adjusted for variables in model 1 plus smoking, drinking and regular exercise. Model 3 was adjusted for variables in model 2 plus BMI, hypertension, diabetes, heart disease, and respiratory disease. Table 3. Associations of sarcopenia, handgrip strength, and calf circumference with cognitive impairment
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The results of multiple linear regression were consistent with those of multiple logistic regression. Sarcopenia was negatively associated with MMSE score (Table 4). Compared with participants without sarcopenia, the fully adjusted model showed a statistically significant negative association (β = –2.16; 95% CI: –2.88, –1.43; P < 0.001). Handgrip strength and calf circumference were positively associated with MMSE score (Table 4). Compared with individuals in Q1 of calf circumference, the adjusted differences in Q2, Q3, and Q4 were 1.73 (95% CI: 0.96, 2.50; P < 0.001), 2.22 (95% CI: 1.39, 3.04; P < 0.001), and 2.28 (95% CI: 1.38, 3.17; P < 0.001), respectively. Compared with individuals in Q1 of handgrip strength, the adjusted differences in Q2, Q3, and Q4 were 2.21 (95% CI: 1.44, 2.98; P < 0.001), 3.58 (95% CI: 2.71, 4.44; P < 0.001), and 3.03 (95% CI: 1.98, 4.08; P < 0.001), respectively.
Independent variables Crude Model Model 1 Model 2 Model 3 β (95% CI) P value β (95% CI) P value β (95% CI) P value β (95% CI) P value Sarcopenia No 0.00 [Reference] 0.00 [Reference] 0.00 [Reference] 0.00 [Reference] Yes −4.31
(−5.03, −3.60)< 0.001 −2.18
(−2.91, −1.46)< 0.001 −2.16
(−2.88, −1.43)< 0.001 −1.97
(−2.72, −1.22)< 0.001 Calf circumference (cm) 0.55 (0.48, 0.62) < 0.001 0.20 (0.13, 0.27) < 0.001 0.20 (0.13, 0.27) < 0.001 0.22 (0.14, 0.29) < 0.001 Calf circumference quartile Q1 (n = 584, 19−27 cm) 0.00 [Reference] 0.00 [Reference] 0.00 [Reference] 0.00 [Reference] Q2 (n = 667, 28−30 cm) 3.59 (2.76, 4.42) < 0.001 1.78 (1.01, 2.54) < 0.001 1.79 (1.02, 2.55) < 0.001 1.73 (0.96, 2.50) < 0.001 Q3 (n = 638, 31−33 cm) 5.54 (4.71, 6.38) < 0.001 2.25 (1.45, 3.06) < 0.001 2.25 (1.44, 3.06) < 0.001 2.22 (1.39, 3.04) < 0.001 Q4 (n = 636, 34−43 cm) 6.39 (5.56, 7.22) < 0.001 2.20 (1.36, 3.04) < 0.001 2.19 (1.35, 3.03) < 0.001 2.28 (1.38, 3.17) < 0.001 Handgrip strength (kg) 0.33 (0.30, 0.36) < 0.001 0.12 (0.08, 0.16) < 0.001 0.12 (0.08, 0.16) < 0.001 0.12 (0.08, 0.16) < 0.001 Handgrip strength quartile Q1 (n = 612, 0.0−9.8 kg) 0.00 [Reference] 0.00 [Reference] 0.00 [Reference] 0.00 [Reference] Q2 (n = 660, 10.0−16.8 kg) 3.77 (2.97, 4.57) < 0.001 2.22 (1.45, 2.99) < 0.001 2.24 (1.47, 3.01) < 0.001 2.21 (1.44, 2.98) < 0.001 Q3 (n = 635, 17.0−24.3 kg) 7.06 (6.26, 7.85) < 0.001 3.55 (2.68, 4.42) < 0.001 3.57 (2.71, 4.44) < 0.001 3.58 (2.71, 4.44) < 0.001 Q4 (n = 618, 24.5−45.8 kg) 8.42 (7.62, 9.21) < 0.001 2.96 (1.91, 4.00) < 0.001 2.98 (1.94, 4.03) < 0.001 3.03 (1.98, 4.08) < 0.001 Note. CI, confidence interval; Model 1: Multivariate logistic analysis was performed after adjusting for age, gender, nationality, education attainment, and marital status. Model 2 was adjusted for variables in model 1 plus smoking, drinking and regular exercise, Model 3 was adjusted for variables in model 2 plus BMI, hypertension, diabetes, heart disease, and respiratory disease. MMSE, Mini-mental state examination. Table 4. Associations of sarcopenia, handgrip strength, and calf circumference with MMSE score
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The RCS curve showed that handgrip strength had an L shaped association and calf circumference had an inverse J shaped association with the prevalence of cognitive impairment (P non-linearity < 0.01). When handgrip strength was less than 20 kg, the OR value for cognitive impairment decreased sharply with increased handgrip strength; when handgrip strength was more than 20 kg, the OR value for cognitive impairment decreased slowly with increasing increments of handgrip strength, and finally tended to be flat. Participants with 32 cm calf circumference had the minimum OR value for cognitive impairment (Figure 2).
Figure 2. Odds ratios for cognitive impairment by grip strength and calf circumference in restricted cubic splines models. Adjusted dose-response associations of handgrip strength (A) and calf circumference (B) with cognitive impairment was delineated using splines. The red line and light green shading indicate OR and 95% CI. The reference value (OR = 1) was set at the 0 kg (0 th percentile) for handgrip strength and 19 cm (0 th percentile) for calf circumference. ORs were adjusted for age, gender, nationality, education attainment, marital status, smoking, drinking, physical exercise, BMI, hypertension, diabetes, heart disease, and respiratory disease. The histogram represents the frequency distribution of handgrip strength (A) and calf circumference (B) in the study sample.
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We conducted stratified analyses according to potential risk factors. The associations of sarcopenia with cognitive impairment were stronger among female (P for interaction = 0.004) and oldest old (P for interaction < 0.001; Figure 3) participants. The associations of calf circumference with cognitive impairment were stronger among female (P for interaction = 0.004) and oldest old (P for interaction < 0.001; Supplementary Figure S2 available in www.besjournal.com) participants. The associations of handgrip strength with cognitive impairment were stronger among participants who were 65−79 years (P for interaction = 0.005), participants who did not perform regular exercise (P for interaction = 0.020) and participants who did not have diabetes (P for interaction = 0.017; Supplementary Figure S2). No other significant interactions were found (all P for interaction ≥ 0.05; Figure 3 and Supplementary Figure S2).
Figure 3. Stratified analyses of associations of sarcopenia with cognitive impairment in logistic regression models among Chinese older adults. CI, confidence interval; OR, odd ratio. Groups were stratified based on eight variables (listed in subgroups). Adjusted covariates included age, gender, nationality, education attainment, marital status, smoking, drinking, regular exercise, BMI, hypertension, diabetes, heart disease, and respiratory disease (When stratified by gender, the adjusted covariables in the model excluded gender, and when stratified by age, the adjusted covariables in the model excluded age, and so on)
Sensitivity analyses showed no substantial change when we excluded participants with major chronic diseases (hypertension, diabetes, heart disease, and respiratory diseases) (Supplementary Table S3 available in www.besjournal.com). The results did not change substantially when we used the maximum grip strength value of the dominant hand (Supplementary Table S4 available in www.besjournal.com), included the outliers of grip strength and calf circumference (Supplementary Table S5 available in www.besjournal.com), added the frequency of vegetable, egg, meat, and fish consumption in model 2 (Supplementary Table S6 available in www.besjournal.com), or added dyslidemia in model 3 (Supplementary Table S7 available in www.besjournal.com).
Independent variables Crude model Model 1 Model 2 Model 3 OR (95% CI) P value OR (95% CI) P value OR (95% CI) P value OR (95% CI) P value Sarcopenia No 1.00 [Reference] 1.00 [Reference] 1.00 [Reference] 1.00 [Reference] Yes 5.37 (2.78−10.39) < 0.001 2.22 (1.06−4.67) 0.035 2.22 (1.05−4.70) 0.037 2.23 (1.05−4.74) 0.038 Calf circumference (cm) 0.84 (0.81−0.88) < 0.001 0.94 (0.89−0.99) 0.031 0.94 (0.89−1.00) 0.037 0.94 (0.89−0.99) 0.018 Calf circumference quartile Q1 1.00 [Reference] 1.00 [Reference] 1.00 [Reference] 1.00 [Reference] Q2 0.41 (0.26−0.65) < 0.001 0.65 (0.38−1.09) 0.104 0.61 (0.36−1.03) 0.064 0.6 (0.35−1.03) 0.062 Q3 0.21 (0.13−0.36) < 0.001 0.50 (0.27−0.93) 0.029 0.5 (0.27−0.94) 0.031 0.48 (0.26−0.91) 0.023 Q4 0.15 (0.09−0.27) < 0.001 0.63 (0.31−1.28) 0.200 0.65 (0.32−1.32) 0.232 0.58 (0.28−1.21) 0.147 Handgrip strength (kg) 0.88 (0.86−0.90) < 0.001 0.94 (0.91−0.98) 0.001 0.94 (0.91−0.97) 0.001 0.94 (0.91−0.97) < 0.001 Handgrip strength quartile Q1 1.00 [Reference] 1.00 [Reference] 1.00 [Reference] 1.00 [Reference] Q2 0.26 (0.16−0.42) < 0.001 0.34 (0.2−0.59) < 0.001 0.32 (0.19−0.56) < 0.001 0.32 (0.18−0.55) < 0.001 Q3 0.11 (0.06−0.19) < 0.001 0.29 (0.15−0.56) < 0.001 0.25 (0.13−0.5) < 0.001 0.25 (0.13−0.49) < 0.001 Q4 0.05 (0.02−0.09) < 0.001 0.25 (0.10−0.58) < 0.001 0.24 (0.10−0.57) < 0.001 0.23 (0.10−0.56) < 0.001 Note. Handgrip Strength was calcaulated by the highest value of dominant hand; OR, odds ratio; CI, confidence interval; Model 1: Multivariate logistic analysis was performed after adjusting for age, gender, nationality, education attainment, and marital status. Model 2 was adjusted for variables in model 1 plus smoking, drinking and physical exercise, Model 3 was adjusted for variables in model 2 plus BMI. Table S3. Associations of handgrip strength, calf circumference and sarcopenia with cognitive impairment (excluding participants with chronic disease)
Independent variables Crude model Model 1 Model 2 Model 3 OR (95% CI) P value OR (95% CI) P value OR (95% CI) P value OR (95% CI) P value Sarcopenia No 1.00 [Reference] 1.00 [Reference] 1.00 [Reference] 1.00 [Reference] Yes 5.33 (4.13−6.89) < 0.001 3.18 (2.41−4.20) < 0.001 3.18 (2.40−4.20) < 0.001 3.04 (2.28−4.04) < 0.001 Handgrip strength (kg) 0.90 (0.89−0.91) < 0.001 0.96 (0.94−0.97) < 0.001 0.96 (0.94−0.97) < 0.001 0.96 (0.94−0.97) < 0.001 Handgrip strength quartile Q1 1.00 [Reference] 1.00 [Reference] 1.00 [Reference] 1.00 [Reference] Q2 0.39 (0.31−0.50) < 0.001 0.59 (0.46−0.76) < 0.001 0.58 (0.45−0.75) < 0.001 0.58 (0.45−0.75) < 0.001 Q3 0.15 (0.11−0.19) < 0.001 0.36 (0.27−0.48) < 0.001 0.35 (0.26−0.47) < 0.001 0.35 (0.26−0.47) < 0.001 Q4 0.08 (0.06−0.11) < 0.001 0.37 (0.25−0.54) < 0.001 0.36 (0.25−0.53) < 0.001 0.35 (0.24−0.52) < 0.001 Note. Handgrip Strength was calcaulated by the highest value of dominant hand; OR, odds ratio; CI, confidence interval; Model 1: Multivariate logistic analysis was performed after adjusting for age, gender, nationality, education attainment, and marital status. Model 2 was adjusted for variables in model 1 plus smoking, drinking and physical exercise, Model 3 was adjusted for variables in model 2 plus BMI, hypertension, diabetes, heart disease, and respiratory disease. Table S4. Associations of handgrip strength (the maximum value of the dominant hand) and sarcopenia with cognitive impairment
Independent variables Crude model Model 1 Model 2 Model 3 OR (95% CI) P value OR (95% CI) P value OR (95% CI) P value OR (95% CI) P value Sarcopenia No 1.00 [Reference] 1.00 [Reference] 1.00 [Reference] 1.00 [Reference] Yes 4.97 (3.76−6.57) < 0.001 2.83 (2.09−3.83) < 0.001 2.81 (2.08−3.81) < 0.001 2.65 (1.95−3.62) < 0.001 Calf circumference (cm) 0.88 (0.86−0.90) < 0.001 0.97 (0.95−0.99) 0.002 0.97 (0.95−0.99) 0.002 0.97 (0.94−0.99) 0.002 Calf circumference quartile Q1 1.00 [Reference] 1.00 [Reference] 1.00 [Reference] 1.00 [Reference] Q2 0.47 (0.37−0.59) < 0.001 0.75 (0.59−0.97) 0.028 0.75 (0.59−0.97) 0.029 0.76 (0.59−0.98) 0.032 Q3 0.25 (0.20−0.32) < 0.001 0.60 (0.45−0.79) 0.000 0.60 (0.45−0.80) 0.000 0.60 (0.45−0.80) < 0.001 Q4 0.19 (0.15−0.24) < 0.001 0.63 (0.46−0.84) 0.002 0.62 (0.46−0.84) 0.002 0.60 (0.43−0.82) 0.002 Handgrip strength (kg) 0.89 (0.88−0.90) < 0.001 0.94 (0.93−0.96) < 0.001 0.94 (0.93−0.96) < 0.001 0.94 (0.92−0.95) < 0.001 Handgrip strength quartile Q1 1.00 [Reference] 1.00 [Reference] 1.00 [Reference] 1.00 [Reference] Q2 0.35 (0.28−0.44) < 0.001 0.49 (0.39−0.63) < 0.001 0.48 (0.38−0.62) < 0.001 0.49 (0.38−0.62) < 0.001 Q3 0.13 (0.10−0.16) < 0.001 0.31 (0.23−0.41) < 0.001 0.30 (0.22−0.41) < 0.001 0.30 (0.22−0.40) < 0.001 Q4 0.07 (0.05−0.09) < 0.001 0.30 (0.21−0.44) < 0.001 0.29 (0.20−0.43) < 0.001 0.29 (0.20−0.42) < 0.001 Note. OR, odds ratio; CI, confidence interval; Model 1: Multivariate logistic analysis was performed after adjusting for age, gender, nationality, education attainment, and marital status. Model 2 was adjusted for variables in model 1 plus smoking, drinking and physical exercise, Model 3 was adjusted for variables in model 2 plus BMI, hypertension, diabetes, heart disease, and respiratory disease. Table S5. Associations of sarcopenia, handgrip strength and calf circumference (including outliers) with cognitive impairment
Independent variables Crude model Model 1 Model 2 Model 3 OR (95% CI) P value OR (95% CI) P value OR (95% CI) P value OR (95% CI) P value Sarcopenia No 1.00 [Reference] 1.00 [Reference] 1.00 [Reference] 1.00 [Reference] Yes 4.81 (3.62−6.40) < 0.001 2.73 (2.00−3.71) < 0.001 2.61 (1.91−3.58) < 0.001 2.46 (1.79−3.39) < 0.001 Calf circumference (cm) 0.86 (0.85−0.88) < 0.001 0.96 (0.93−0.98) < 0.001 0.96 (0.94−0.98) 0.001 0.96 (0.93−0.98) 0.001 Calf circumference quartile Q1 1.00 [Reference] 1.00 [Reference] 1.00 [Reference] 1.00 [Reference] Q2 0.46 (0.37−0.58) < 0.001 0.75 (0.58−0.96) 0.023 0.75 (0.58−0.97) 0.026 0.74 (0.57−0.96) 0.025 Q3 0.25 (0.19−0.31) < 0.001 0.59 (0.45−0.78) < 0.001 0.59 (0.44−0.78) < 0.001 0.58 (0.43−0.78) < 0.001 Q4 0.19 (0.15−0.25) < 0.001 0.64 (0.48−0.87) 0.004 0.66 (0.48−0.90) 0.008 0.63 (0.45−0.88) 0.007 Handgrip strength (kg) 0.89 (0.88−0.90) < 0.001 0.94 (0.93−0.96) < 0.001 0.94 (0.93−0.96) < 0.001 0.94 (0.93−0.96) < 0.001 Handgrip strength quartile Q1 1.00 [Reference] 1.00 [Reference] 1.00 [Reference] 1.00 [Reference] Q2 0.35 (0.28−0.44) < 0.001 0.50 (0.39−0.63) < 0.001 0.48 (0.38−0.62) < 0.001 0.49 (0.38−0.63) < 0.001 Q3 0.13 (0.10−0.17) < 0.001 0.32 (0.23−0.43) < 0.001 0.31 (0.23−0.42) < 0.001 0.31 (0.23−0.42) < 0.001 Q4 0.07 (0.05−0.10) < 0.001 0.32 (0.22−0.46) < 0.001 0.33 (0.22−0.49) < 0.001 0.32 (0.22−0.48) < 0.001 Note. OR, odds ratio; CI, confidence interval; Model 1: Multivariate logistic analysis was performed after adjusting for age, gender, nationality, education attainment, and marital status. Model 2 was adjusted for variables in model 1 plus smoking, drinking, physical exercise, intake frequencies of vegetables, eggs, meat and fish (almost every day, at least once a week, at least once a month, sometimes, or rarely). Model 3 was adjusted for variables in model 2 plus BMI, hypertension, diabetes, heart disease, and respiratory disease. Table S6. Associations of sarcopenia, handgrip strength and calf circumference with cognitive impairment (food consumption was added to model 2)
Independent variables Crude model Model 1 Model 2 Model 3 OR (95% CI) P value OR (95% CI) P value OR (95% CI) P value OR (95% CI) P value Sarcopenia No 1.00 [Reference] 1.00 [Reference] 1.00 [Reference] 1.00 [Reference] Yes 4.81 (3.62−6.40) < 0.0001 2.73 (2.00−3.71) < 0.0001 2.72 (1.99−3.70) < 0.0001 2.53 (1.85−3.48) < 0.001 Calf circumference (cm) 0.86 (0.85−0.88) < 0.0001 0.96 (0.93−0.98) 0.001 0.96 (0.93−0.98) 0.001 0.95 (0.93−0.98) 0.001 Calf circumference quartile Q1 1.00 [Reference] 1.00 [Reference] 1.00 [Reference] 1.00 [Reference] Q2 0.46 (0.37−0.58) < 0.0001 0.75 (0.58−0.96) 0.023 0.74 (0.58−0.96) 0.023 0.73 (0.56−0.94) 0.015 Q3 0.25 (0.19−0.31) < 0.0001 0.59 (0.45−0.78) 0.000 0.59 (0.45−0.79) 0.000 0.59 (0.44−0.79) < 0.001 Q4 0.19 (0.15−0.25) < 0.0001 0.64 (0.48−0.87) 0.004 0.64 (0.47−0.87) 0.004 0.62 (0.45−0.86) 0.004 Handgrip strength (kg) 0.89 (0.88−0.90) < 0.0001 0.94 (0.93−0.96) < 0.0001 0.94 (0.93−0.96) < 0.0001 0.94 (0.93−0.96) < 0.001 Handgrip strength quartile Q1 1.00 [Reference] 1.00 [Reference] 1.00 [Reference] 1.00 [Reference] Q2 0.35 (0.28−0.44) < 0.0001 0.50 (0.39−0.63) < 0.0001 0.49 (0.38−0.62) < 0.0001 0.49 (0.39−0.63) < 0.001 Q3 0.13 (0.10−0.17) < 0.0001 0.32 (0.23−0.43) < 0.0001 0.31 (0.23−0.42) < 0.0001 0.31 (0.23−0.41) < 0.001 Q4 0.07 (0.05−0.10) < 0.0001 0.32 (0.22−0.46) < 0.0001 0.31 (0.21−0.45) < 0.0001 0.31 (0.21−0.45) < 0.001 Note. OR, odds ratio; CI, confidence interval; Model 1: Multivariate logistic analysis was performed after adjusting for age, gender, nationality, education attainment, and marital status. Model 2 was adjusted for variables in model 1 plus smoking, drinking and physical exercise, Model 3 was adjusted for variables in model 2 plus BMI, hypertension, diabetes, heart disease, respiratory disease and dyslipidemia. Table S7. Associations of sarcopenia, handgrip strength and calf circumference with cognitive impairment (dyslipidemia was added to model 3)
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X-MS had full access to all the data in the study and takes responsibility for the integrity of the data and the accuracy of the data analysis. BW, Y-BL contributed to the study concept, collected and assembled the data, analysed and interpreted the data, and drafted the manuscript. Z-JC, YW, W-YS, J-HZ, CM, and X-MS helped to implement the survey and contributed to the concept and data analysis. XG, VBK, FZ, XC, FL, M-YZ, and Y-CL helped to interpret the results and provided critical revisions. Q-YT, S-XS, Y-LQ, and X-LZ helped with correction of the manuscript.
Variables Total Sarcopenia Non-sarcopenia (N = 2,525) (N = 2,032) (N = 493) Age (years) 84.50 (84.06−84.94) 87.23 (86.77−87.69) 73.27 (72.71−73.83) Handgrip strength 17.58 (17.20−17.95) 14.93 (14.59−15.28) 28.47 (27.80−29.14) Calf circumference 30.58 (30.40−30.75) 29.58 (29.41−29.75) 34.67 (34.39−34.96) Education attainment (years) 2.66 (2.53−2.79) 2.11 (1.98−2.25) 4.90 (4.59−5.22) Cognitive impairment (%) Yes 0.35 (0.33−0.36) 0.4 (0.38−0.42) 0.12 (0.09−0.15) No 0.65 (0.64−0.67) 0.6 (0.58−0.62) 0.88 (0.85−0.91) Nationality Han 0.91 (0.90−0.93) 0.91 (0.90−0.92) 0.92 (0.90−0.95) Minority 0.09 (0.07−0.10) 0.09 (0.08−0.10) 0.08 (0.05−0.10) Gender (%) Male 0.48 (0.46−0.50) 0.47 (0.45−0.50) 0.49 (0.45−0.54) Female 0.52 (0.50−0.54) 0.53 (0.50−0.55) 0.51 (0.46−0.55) Current marital status (%) Married 0.99 (0.99−0.99) 0.99 (0.99−1.00) 0.99 (0.98−1.00) Unmarried 0.01 (0.00−0.01) 0.01 (0.00−0.02) 0.01 (0.01−0.01) Smoking (%) Yes 0.17 (0.16−0.19) 0.17 (0.15−0.18) 0.19 (0.16−0.23) No 0.83 (0.81−0.84) 0.83 (0.82−0.85) 0.81 (0.77−0.84) Alcohol consumption (%) Yes 0.18 (0.16−0.19) 0.16 (0.15−0.18) 0.84 (0.82−0.85) No 0.82 (0.81−0.84) 0.23 (0.19−0.26) 0.77 (0.74−0.81) Exercise (%) Yes 0.20 (0.19−0.22) 0.18 (0.16−0.19) 0.32 (0.28−0.36) No 0.80 (0.78−0.81) 0.32 (0.28−0.36) 0.68 (0.64−0.72) Hypertension (%) Yes 0.70 (0.68−0.72) 0.69 (0.67−0.71) 0.75 (0.71−0.79) No 0.30 (0.28−0.32) 0.31 (0.29−0.33) 0.25 (0.21−0.29) Diabetes (%) Yes 0.13 (0.12−0.15) 0.13 (0.11−0.14) 0.15 (0.11−0.18) No 0.87 (0.85−0.88) 0.87 (0.86−0.89) 0.85 (0.82−0.89) Heart disease (%) Yes 0.11 (0.09−0.12) 0.1 (0.09−0.12) 0.12 (0.09−0.15) No 0.89 (0.88−0.91) 0.9 (0.88−0.91) 0.88 (0.85−0.91) Respiratory diseases (%) Yes 0.09 (0.08−0.10) 0.09 (0.08−0.10) 0.06 (0.04−0.09) No 0.91 (0.90−0.93) 0.91 (0.9−0.92) 0.94 (0.91−0.96) Table S2. Characteristics of participants according to sarcopenia status
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Study Population
Assessment of Cognitive Impairment
Screening for Sarcopenia
Assessment of Covariates
Statistical Analyses
Participants’ Characteristics
Associations of Sarcopenia, Handgrip Strength and Calf Circumference with Cognitive Impairment
Association of Sarcopenia, Handgrip Strength and Calf Circumference with MMSE Score
Dose-Response Associations of Handgrip Strength and Calf Circumference with Cognitive Impairment
Subgroup Analysis and Sensitivity Analysis
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