Assessment of the effects of glutamic acid decarboxylase antibodies and trace elements on cognitive performance in older adults

Figures & data

Table 1 General characteristics of subjects

Parameters	Participants (n=100; mean ± SD)
Male/female	65/35
Age (years)	65.2±3.6
Education (some college) (%)	80
BMI (kg/m^2)	22.8±3.2
Waist (cm)	71.3±4.7
Hips (cm)	86.7±12.3
WHR	0.82±0.10
Systolic BP (mmHg)	115.5±7.3
Diastolic BP (mmHg)	72.9±2.3
Mean HbA1c value, % (SD)	4.5±0.35
VO2 max (mL/kg min)	37.4±3.7
Mean LOTCA score (SD)	111.2±3.5
LTPA (MET-H/week)	125.2±4.3

Notes: Values are expressed as mean ± SD; Significance at P<0.05.

Abbreviations: BP, blood pressure; BMI, body mass index; LOTCA, Loewenstein Occupational Therapy Cognitive Assessment score; LTPA, leisure-time physical activity; WHR, waist to hip ratio; BMR, basal metabolic rate (kcal/day); VO2 max, maximal oxygen consumption; MET-H, metabolic equivalent in hours.

Table 2 Cognitive performance in the studies population based on LOTCA-7 scores (n=100)

Parameters	Normal (93–123), n=45	Moderate (62–92), n=30	Severe (31–62), n=25
Orientation	14.5±2.3	11.2±1.2**	7.5±1.5**
Visual perception	18.2±3.2	13.5±3.1**	8.6±1.7**
Spatial perception	11.8±0.8	6.4±0.6**	6.9±0.9**
Motor praxis	9.7±0.75	6.8±0.56**	5.3±0.81**
Vasomotor organization	26.7±3.4	18.1±4.3**	12.3±2.4**
Thinking operations	25.5±4.1	16.2±2.7**	11.4±3.9**
Attention and concentration	4.8±0.72	2.9±4.3**	1.8±0.76**
Total LOTCA score	111.2±3.5	75.1±4.1**	53.8±6.1**

Notes: Values are expressed as mean ± SD;

** P<0.01. Significance at P<0.05.

Abbreviation: LOTCA, Loewenstein Occupational Therapy Cognitive Assessment score.

Table 3 Associations of serum trace elements, HbA_1c, BMI, WHR, and anti-GADAs titers with cognitive performance of older adults (n=100)

Variables	Cognitive performance (LOTCA score)
	Normal (93–123), n=45	Moderate (62–92), n=30	Severe (31–62), n=25
BMI (kg/m^2)	22.8±3.2	23.8±5.3*	24.9±6.1*
WHR	0.82±0.10	0.92±0.18*	0.98±0.21*
HbA1c%	4.2±0.51	5.7±0.38**	6.3±0.65**
LTPA (MET-H/week)	125.2±4.3	98.5±7.1**	48±2.3**
GADAs (U/mL)	3.5±0.85	5.7±2.6**	9.6±4.2**
Fe (µg/dL)	68.5±6.3	98.2±3.5*	114.2±1.9**
Cu (µg/dL)	102.3±6.3	123.4±4.7*	142.3±6.9**
Zn (µg/dL)	78.3±2.5	65.4±1.6*	48.9±3.4**
Zn/Cu ratio	0.78±0.95	0.53±0.62*	0.34±0.78**

Notes: Values are expressed as mean ± SD;

* P<0.05,

** P<0.01. Significance at P<0.05.

Abbreviations: BMI, body mass index; GADAs, glutamic acid decarboxylase antibody; LOTCA, Loewenstein Occupational Therapy Cognitive Assessment score; LTPA, leisure-time physical activity; WHR, waist to hip ratio; MET-H, metabolic equivalent in hours.

Table 4 Serum trace elements concentrations in studied population based on anti-GADAs titers (n=100)

Variables	GADAs negative (<5 U/mL); (n=50)	GADAs positive (≥5 U/mL); (n=50)
Fe (µg/dL)	86.5±12.4	110.5±6.3**
Cu (µg/dL)	118.2±15.2	138.6±15.1**
Zn (µg/dL)	89.7±4.8	56.4±6.3**
Zn/Cu ratio	0.76±0.85	0.41±0.56**
HbA1c %	3.92±0.58	5.82±0.35**

Notes: Values are expressed as mean ± SD;

** P<0.01. Significance at P<0.05.

Abbreviation: GADAs, glutamic acid decarboxylase antibody.

Table 5 Results of stepwise multiple regression analysis of cognitive ability predicted by serum trace elements, and anti-GADAs, and demographic related variables

Variables	Cognitive performance (LOTCA score)
	Normal (93–123), n=45		Moderate (62–92), n=30		Severe (31–62), n=25
	β	R^2	β	R^2	β	R^2
Age (years)	−0.045*	0.542	−0.035*	0.325	−0.029*	0.385
Sex	0.082*		0.55*		0.035*
BMI (kg/m^2)	−0.023*		−0.045**		−0.065**
WHR	−0.035*		−0.065**		−0.045**
HbA1c%	0.075*		0.035**		0.028**
Physical activity	−0.425*		−0.358**		−0.298**
Anti-GADAs titer (U/mL)	−0.541*		−0.387**		−0.595**
Fe (µg/dL)	0.042*		0.075**		0.086**
Cu (µg/dL)	0.031*		0.049**		0.048**
Zn (µg/dL)	0.058*		0.061**		0.059**
Zn/Cu ratio	0.036*		0.037**		0.045**

Notes: Estimated standardized regression coefficients (β) and variance explained (R²) are presented. Significance at

* P<0.05,

** P<0.01.

Abbreviations: GADAs, glutamic acid decarboxylase antibody; BMI, body mass index; LOTCA, Loewenstein Occupational Therapy Cognitive Assessment score; WHR, waist to hip ratio.

Table 6 Correlation of LOTCA cognitive function scores with serum trace elements, and anti-GADAs of older adults (n=100)

Parameters	Trace elementsa				GADAsa
	Fe (µg/dL)	Cu (µg/dL)	Zn (µg/dL)	Zn/Cu ratio
Orientation	−0.45*	−0.012*	0.48*	0.71*	−0.25*
Visual perception	−0.65*	−0.25*	0.65*	0.55*	−0.65*
Spatial perception	−0.85*	−0.17*	0.81*	0.74*	−0.49*
Motor praxis	−0.89*	−0.42*	0.45*	0.63*	−0.39*
Vasomotor organization	−0.561*	−0.51*	0.54*	0.38*	−0.58*
Thinking operations	−0.047*	−0.32*	0.42*	0.45*	−0.64*
Attention and concentration	−0.054*	−0.31*	0.39*	0.31*	−0.31*
Total LOTCA score	−0.125*	−0.28*	0.58*	0.88*	−0.78*

Notes:

a Estimated standardized regression coefficients (β) and variance explained (R²) are presented. Significance at

* P<0.05.

Abbreviations: GADAs, glutamic acid decarboxylase antibody; LOTCA, Loewenstein Occupational Therapy Cognitive Assessment score.