Dynamic sitting: Measurement and associations with metabolic health

Figures & data

Figure 1. Percentage dynamic sitting, sedentary, and active minutes of total activity time. In brackets the number of participants who recorded dynamic sitting.

Table 1. Descriptive characteristics of the average counts per minute in each axis for each activity.

		V axis	AP axis	ML axis
Natural sitting	Range (min-max)	0.00–39.80	0.00–87.20	0.00–115.00
	Mean (SD)	6.74 (11.14)	12.41 (22.59)	14.00 (28.94)
	Median [Q1-Q3]	0.30 [0.00–12.05]	2.60 [0.45–14.50]	0.00 [0.00–19.65]
Imposed sitting	Range (min-max)	0.00–11.80	0.00–24.20	0.00–14.40
	Mean (SD)	1.96 (3.86)	4.40 (8.50)	2.07 (4.38)
	Median [Q1-Q3]	0.00 [0.00–1.75]	0.00 [0.00–3.55]	0.00 [0.00–1.40]
Imposed fidgeting	Range (min-max)	0.00–2607.25	2.25–4777.50	0.00–6508.25
	Mean (SD)	625.07 (613.76)	1766.51 (1080.12)	2048.38 (1769.87)
	Median [Q1-Q3]	516.88 [210.44–795.44]	1630.25 [1184.56–2248.50]	1679.13 [1008.25–2470.31]
Reading	Range (min-max)	0.00–25.14	0.00–52.43	0.00–58.71
	Mean (SD)	3.66 (6.70)	12.41 (14.81)	9.40 (15.82)
	Median [Q1-Q3]	0.29 [0.00–5.07]	5.71 [0.64–19.39]	2.64 [0.75–8.86]
Writing	Range (min-max)	0.00–0.86	0.00–39.71	0.00–7.14
	Mean (SD)	0.08 (0.22)	3.33 (9.24)	1.04 (2.00)
	Median [Q1-Q3]	0.00 [0.00–0.00]	0.07 [0.00–3.00]	0.00 [0.00–1.39]
Watching TV	Range (min-max)	0.00–49.71	1.29–150.43	0.00–149.14
	Mean (SD)	17.71 (16.01)	39.26 (34.23)	37.40 (42.37)
	Median [Q1-Q3]	14.14 [6.14–24.39]	31.00 [19.93–46.86]	24.71 [10.46–51.32]
Typing	Range (min-max)	0.00–14.57	0.00–62.14	0.00–22.14
	Mean (SD)	1.67 (3.75)	6.05 (14.64)	5.87 (8.04)
	Median [Q1-Q3]	0.00 [0.00–2.39]	0.86 [0.00–5.21]	1.29 [0.00–9.82]
Playing cards	Range (min-max)	0.00–31.00	0.86–236.14	0.00–72.00
	Mean (SD)	6.93 (9.00)	51.37 (53.87)	23.31 (21.05)
	Median [Q1-Q3]	3.50 [0.00–13.21]	42.43 [16.46–65.07]	20.50 [6.46–35.79]
Preparing food	Range (min-max)	0.00–50.43	0.00–163.00	0.00–139.29
	Mean (SD)	10.96 (16.35)	32.86 (44.04)	33.79 (36.38)
	Median [Q1-Q3]	2.07 [0.00–15.75]	13.86 [7.68–34.5]	23.64 [7.11–53.43]

V, vertical axis; AP, anteroposterior; ML, mediolateral.

Table 2. Characteristics of the AGES-Reykjavik study sample.

	Sex-specific quartiles of minutes recorded as dynamic sitting:
	1 (fewest)		2		3		4 (most)
Cut-off points for the quartiles (min/day)	48.0–112.7		103.4–145.3		129.4–177.4		161.3–330.9		P-value
Age (years)	79.8	(4.7)	79.6	(4.8)	80.1	(4.4)	80.6	(5.0)	0.282
Educational level (%)									0.154
● primary	16.6		20.8		22.4		20.9
● secondary	54.8		53.9		45.4		50.0
● college/university	28.6		25.3		32.2		29.1
Weight status (%)									<0.001
● BMI <25	21.7		33.1		37.5		50.0
● 25 ≤ BMI <30	40.1		42.9		39.5		39.9
● BMI≥30	38.2		24.0		23.0		10.1
Smoking status (% current)	14.6		7.8		7.2		6.3		0.062
Alcohol consumption (grams/week)	14.8	(35.5)	12.5	(22.2)	20.9	(51.2)	13.1	(24.7)	0.140
Health status (% with heart disease, TIA, stroke or diabetes mellitus)	33.1		32.5		21.7		23.4		0.042
Mobility limitation (% limited)	47.1		35.7		28.9		35.4		0.010
Medication use (% antidiabetic or antihypertensive)	77.1		74.0		67.8		70.9		0.291
BMI (kg/m^2)	28.7	(5.0)	27.2	(3.9)	26.6	(4.6)	25.1	(3.9)	<0.001
Waist circumference (cm)	104.5	(12.3)	100.9	(11.4)	100.3	(12.6)	95.5	(11.1)	<0.001
HDL cholesterol (mmol/L)	1.5	(0.4)	1.6	(0.4)	1.6	(0.5)	1.7	(0.5)	0.001
Triglycerides (mmol/L)	1.2	[0.9–1.6]	1.1	[0.9–1.4]	1.1	[0.8–1.4]	1.0	[0.8–1.2]	<0.001
Fasting glucose (mmol/L)	5.6	[5.2–6.1]	5.6	[5.2–6.1]	5.5	[5.1–6.1]	5.4	[5.1–5.8]	0.018
C-reactive protein (mg/L)	2.0	[0.9–3.8]	1.9	(1.0–4.2]	2.0	[0.9–3.9]	1.4	[0.7–3.0]	0.031
Systolic blood pressure (mmHg)	141.2	(18.6)	145.7	(19.4)	144.1	(21.5)	146.9	(24.7)	0.096
Diastolic blood pressure (mmHg)	70.9	(10.0)	70.2	(11.4)	70.0	(11.6)	69.9	(11.8)	0.775
Metabolic syndrome (%)	51.0		43.5		38.8		27.8		<0.001
Number of valid days (≥10h monitoring/day)	5.7	(1.6)	6.0	(1.3)	6.2	(1.3)	6.2	(1.3)	0.004
Wear time (h/day)	13.2	(1.5)	13.6	(1.4)	13.9	(1.6)	14.1	(1.3)	<0.001
MVPA (min/day)	2.0	[0.6–8.3]	2.5	[0.8–11.3]	1.6	[0.6–7.6]	1.9	[0.7–10.2]	0.195
Sedentary time (h/day)	10.0	(1.5)	10.2	(1.5)	10.4	(1.6)	10.5	(1.3)	0.012
% sedentary time per day	76.2	(8.9)	74.7	(8.7)	75.1	(9.2)	75.0	(9.0)	0.463
Dynamic sitting hours per day	1.5	[1.3–1.7]	2.0	[1.9–2.2]	2.6	[2.5–2.7]	3.3	[3.0–3.7]	<0.001
% dynamic sitting of sedentary time per day	14.8	(3.8)	20.7	(3.6)	25.3	(4.4)	33.0	(6.2)	<0.001

Values are mean (SD), or median [25%–75%], unless stated otherwise. TIA, transient ischemic attack; BMI, body mass index; MVPA, moderate to vigorous physical activity. N = 621; 60 men and 95 women in each quartile. Boldface indicates statistical significance (P < 0.05).

Table 3. Associations between dynamic sitting and cardio-metabolic outcomes.

		Models 1		Models 2		Models 3
	Dynamic sitting minutes/day	B	(95% CI)	B	(95% CI)	B	(95% CI)
BMI (kg/m^2)	Q1 (fewest)*	ref		ref		ref
	Q2	−1.57	(−2.55; −0.60)	−1.51	(−2.45; −0.56)	−1.39	(−2.33; −0.46)
	Q3	−2.26	(−3.24; −1.28)	−2.31	(−3.26; −1.36)	−1.87	(−2.82; −0.92)
	Q4 (most)	−3.81	(−4.78; −2.84)	−3.65	(−4.59; −2.70)	−3.38	(−4.32; −2.45)
Waist	Q1 (fewest)	ref		ref		ref
circumference	Q2	−3.80	(−6.43; −1.18)	−3.36	(−5.91; −0.80)	−2.95	(−5.44; −0.46)
(cm)	Q3	−4.66	(−7.30; −2.01)	−4.76	(−7.33; −2.19)	−3.47	(−6.01; −0.93)
	Q4 (most)	−9.63	(−12.26; −7.01)	−9.17	(−11.73; −6.62)	−8.21	(−10.72; −5.71)
HDL cholesterol	Q1 (fewest)	ref		ref		ref
(mmol/L)	Q2	0.09	(0.00; 0.19)	0.09	(0.00; 0.18)	0.06	(−0.03; 0.15)
	Q3	0.10	(0.00; 0.20)	0.09	(0.00; 0.18)	0.02	(−0.07; 0.11)
	Q4 (most)	0.24	(0.14; 0.34)	0.22	(0.13; 0.32)	0.13	(0.04; 0.22)
Triglycerides	Q1 (fewest)	1.00		1.00		1.00
(mmol/L)^†	Q2	0.95	(0.87; 1.04)	0.96	(0.88; 1.05)	1.00	(0.92; 1.09)
	Q3	0.94	(0.86; 1.03)	0.94	(0.86; 1.02)	1.01	(0.92; 1.10)
	Q4 (most)	0.81	(0.74; 0.88)	0.82	(0.75; 0.89)	0.91	(0.84; 0.99)
Fasting glucose	Q1 (fewest)	1.00		1.00		1.00
(mmol/L)^†	Q2	1.00	(0.97; 1.04)	1.01	(0.97; 1.04)	1.02	(0.99; 1.04)
	Q3	1.00	(0.96; 1.03)	1.00	(0.96; 1.03)	1.02	(0.99; 1.05)
	Q4 (most)	0.96	(0.92; 0.99)	0.96	(0.93; 0.99)	1.00	(0.97; 1.02)
C-reactive	Q1 (fewest)	1.00		1.00		1.00
protein (mg/L)^†	Q2	1.03	(0.80; 1.32)	1.04	(0.81; 1.34)	1.20	(0.94; 1.53)
	Q3	0.98	(0.76; 1.26)	0.98	(0.76; 1.26)	1.22	(0.95; 1.57)
	Q4 (most)	0.76	(0.59; 0.97)	0.76	(0.60; 0.98)	1.03	(0.80; 1.33)
Systolic blood	Q1 (fewest)	ref		ref		ref
pressure (mmHg)	Q2	4.70	(−0.02; 9.42)	4.30	(−0.41; 9.01)	3.92	(−0.87; 8.71)
	Q3	3.37	(−1.39; 8.12)	3.32	(−1.41; 8.06)	2.71	(−2.21; 7.64)
	Q4 (most)	6.22	(1.50; 10.93)	5.63	(0.92; 10.33)	5.10	(0.12; 10.07)
Diastolic blood	Q1 (fewest)	ref		ref		ref
pressure (mmHg)	Q2	−0.67	(−3.17; 1.83)	−0.88	(−3.33; 1.57)	−0.75	(−3.23; 1.72)
	Q3	−0.84	(−3.35; 1.68)	−0.61	(−3.08; 1.86)	−0.74	(−3.28; 1.80)
	Q4 (most)	−1.15	(−3.65; 1.35)	−0.89	(−3.34; 1.56)	−0.72	(−3.29; 1.85)
		OR	(95% CI)	OR	(95% CI)	OR	(95% CI)
Metabolic	Q1 (fewest)	1.00		1.00		1.00
syndrome	Q2	0.72	(0.46; 1.14)	0.74	(0.47; 1.19)	0.74	(0.45; 1.20)
	Q3	0.58	(0.36; 0.91)	0.55	(0.34; 0.88)	0.58	(0.36; 0.95)
	Q4 (most)	0.34	(0.21; 0.55)	0.35	(0.21; 0.56)	0.36	(0.22; 0.59)

Regression results are presented as unstandardized coefficients (B) and odds ratios (OR) with 95% confidence intervals (95% CI) for metabolic syndrome. Boldface indicates statistical significance (P < 0.05). BMI, body mass index. N = 621; 60 men and 95 women in each quartile. Model 1: adjusted for daily minutes of sedentary time; Model 2: additionally adjusted for sex, age, level of education, and daily minutes of MVPA; Model 3: additionally adjusted for smoking status, alcohol consumption, health status (the metabolic syndrome was not adjusted for diabetes mellitus), and mobility limitation. In model 3, HDL cholesterol, triglycerides, and C-reactive protein were further adjusted for BMI; fasting glucose was further adjusted for BMI and antidiabetic medication; blood pressure was further adjusted for BMI and antihypertensive medication. *Cut-off points for the quartiles were Quartile 1: 48.0–112.7; Quartile 2: 103.4–145.3; Quartile 3: 129.4–177.4; Quartile 4: 161.3–330.9. †Back-transformed from the log scale.