Adolescent physical activity, sedentary behavior and sleep in relation to body composition at age 18 years in urban South Africa, Birth-to-Twenty+ Cohort

Micklesfield, Lisa K.; Hanson, Sara K.; Lobelo, Felipe; Cunningham, Solveig A.; Hartman, Terryl J.; Norris, Shane A.; Stein, Aryeh D.

doi:10.1186/s12887-020-02451-9

Table 3 Regression coefficients (B) and 95% CI for anthropometric and body composition measures at 18y, adjusted, Bt20+

From: Adolescent physical activity, sedentary behavior and sleep in relation to body composition at age 18 years in urban South Africa, Birth-to-Twenty+ Cohort

	BMI (kg/m2)		Waist circumference (cm)		Fat mass index ^a (kg/m2)		Lean mass ^b index ^c (kg/m2)		Body fat (%)
Males
N	B (95% CI)	P-value	B (95% CI)	P-value	B (95% CI)	P-value	B (95% CI)	P-value	B (95% CI)	P-value
Informal activity ^d
Decreasing over time	ref	0.7	ref	0.9	ref	0.5	ref	0.7	ref	0.4
Increasing over time	−0.2(−1.1–0.68)		0.0 (−2.4–2.4)		− 0.2 (− 0.8–0.4)		0.1 (− 0.5–0.7)		−0.9 (− 3.3–1.4)
Organized Sports Participation ^d
Consistently low	ref	0.4	ref	0.2	ref	0.5	ref	0.5	ref	0.4
Decreasing from adequate to low	0.02 (−0.9–0.8)		0.8 (−1.-3.0)	0.5	0.1 (−0.5–0.8)		− 0.2 (− 0.8–0.3)		0.4 (−2.0–2.8)
Increasing from low to adequate	−0.2 (− 1.1–0.7)		−1.6 (− 3.7–0.4)	0.1	− 0.3 (− 0.9–0.3)		0.1 (− 0.4–0.7)		−1.4 (− 3.6–0.8)
Walking to and from school ^d
Consistently 150 min/week	ref	0.7	ref	0.8	ref	0.4	ref	0.8	ref	0.3
Consistently 300 min/week	− 0.1 (−0.7–0.5)		− 0.2 (−1.9–1.5)		− 0.2 (− 0.7–0.3)		0.0 (− 0.4–0.5)		−0.9 (− 2.7–0.9)
Overall physical activity ^e
Model 1 ^d
Decreasing activity over time and do not walk to school	ref	0.02	ref	0.01	ref	0.01	ref	0.5	ref	0.004
Decreasing activity over time but consistently walk to school	−0.8 (−1.4--0.2)		−2.1 (− 3.7--0.4)		− 0.7 (− 1.1–0.2)		−0.2 (− 0.6–0.2)		−2.2 (− 3.8--0.6)
Consistently more active and consistently walk to school	− 0.8 (− 1.5--0.2)		− 2.7 (−4.5−− 0.8)		-0.8 (− 1.3--0.3)		0.0 (− 0.5–0.4)		−3.2 (−5.1--1.3)
Model 2 ^f
Decreasing activity over time and do not walk to school	ref	0.1	ref	0.1	ref	0.02	ref	0.6	ref	0.008
Decreasing activity over time but consistently walk to school	−0.6 (−1.2–0.1)		−1.4 (−3.1–0.3)		− 0.56(− 1.0−− 0.1)		-0.1 (− 0.5–0.3)		−1.9 (− 1.7--0.2)
Consistently more active and consistently walk to school	− 0.6 (− 1.3–0.0)		−2.0 (− 3.9--0.2)		−0.8 (− 1.2--0.1)		0.1 (− 0.4–0.6)		−2.9 (−4.9--0.9)
Sedentary behavior ^d
Consistently low	ref	0.1	ref	0.2	ref	0.2	ref	0.4	ref	0.2
Consistently high	0.6 (−1.3–1.4)		0.1 (−2.1–2.2)		−0.7 (− 1.5–0.2)		−0.2 (− 0.9–0.6)		−2.7 (−5.8–0.5)
Increasing from low to high	0.5 (− 0.2–1.2)		1.8 (− 0.1–3.8)		0.3 (− 0.2–0.8)		0.3 (− 0.2–0.8)		0.6 (− 1.3–2.5)
Schoolnight sleep ^d
≤ 8 h/night	ref		ref		ref		ref		ref
≥ 9 h/night	−1.0 (− 1.4--0.5)	< 0.0001	− 2.3 (− 3.7--1.1)	< 0.0001	− 0.4 (− 0.8--0.1)	0.02	0.1 (− 0.2–0.5)	0.5	−1.5 (− 2.8--0.1)	0.04
Females
N	B (95% CI)	P-value	B (95% CI)	P-value	B (95% CI)	P-value	B (95% CI)	P-value	B (95% CI)	P-value
Informal activity ^d
Decreasing over time	ref	0.2	ref	0.02	ref	0.2	ref	0.2	ref	0.2
Increasing over time	0.9 (−0.4–2.1)		6.0 (0.9–11.1)		0.8 (− 0.5–2.0)		0.4 (− 0.2–1.1)		2.1 (−1.1–5.3)
Organized sports participation ^d
None	ref	0.8	ref	0.6	ref	0.9	ref	0.05	ref	0.6
Consistently some	0.4 (−0.6–1.4)		−1.4 (−5.0–2.7)		0.1 (− 0.9 1.0)		0.5 (0.0–1.0)		− 0.7 (−3.0–1.67
Walking to and from school ^d
Consistently 150 min/week	ref	0.3	ref	0.8	ref	0.7	ref	0.02	ref	0.9
Consistently 300 min/week	0.4 (−0.3–1.1)		0.4 (−3.4–2.6)		0.1 (−0.5–0.8)		0.4 (0.1–0.7)		0.1 (−1.5–1.7)
Overall physical activity ^e
Model 1 ^d
Decreasing activity over time and do not walk to school	ref	0.2	ref	0.09	ref	0.5	ref	0.2	ref	0.6
Decreasing activity over time but consistently walk to school	0.5 (−0.3–1.3)		2.6 (−0.6–5.8)		0.5 (−0.3–1.2)		0.3 (− 0.1–0.7)		0.9 (−1.0–2.7)
Consistently more active and consistently walk to school	0.9 (−0.1–1.9)		4.6 (0.5–8.6)		0.4 (−0.6–1.3)		0.4 (− 0.1–0.9)		0.1 (−2.3–2.6)
Model 2 ^f
Decreasing activity over time and do not walk to school	ref	0.2	ref	0.07	ref	0.5	ref	0.2	ref	0.6
Decreasing activity over time but consistently walk to school	0.5 (−0.3–1.4)		2.9 (− 0.4–6.1)		0.4 (− 0.3–1.2)		0.3 (− 0.1–0.7)		0.8 (−1.1–2.7)
Consistently more active and consistently walk to school	0.9 (− 0.1–2.0)		4.8 (0.7–9.0)		0.4 (− 0.6–1.3)		0.5 (0.0–0.1)		0.1 (−2.3–2.6)
Sedentary behavior ^d
Initially low but increasing	ref	0.08	ref	0.04	ref	0.1	ref	0.7	ref	0.06
Consistently high	−1.1 (−2.4–0.1)	0.08	5.4 (0.2–10.6)		−1.2 (−2.6–0.2)		−0.2 (−0.9–0.6)		−3.5 (−7.0–0.1)
Schoolnight sleep ^d
≤ 8 h/night	ref	0.8	ref	0.6	ref	0.3	ref	0.7	ref	0.7
≥ 9 h/night	0.1 (−0.6–0.8)		0.6 (− 2.2–3.3)		0.3 (− 0.3–0.9)		−0.1 (− 0.4–0.2)		0.3 (− 1.2–1.8)

^a Fat mass index, calculated by dividing fat mass (in kg) by height (in meters) squared
^b Lean mass does not include bone mineral content
^c Lean mass index, calculated by dividing lean mass (in kg) by height (in meters) squared
^d Adjusted for childhood BMIZ at age 7/ 8 or 9 years, birth order, maternal schooling, maternal marital status and SES asset quintile at child age 7/8 years
^e Multi-trajectory groups made up of informal activity, organized sports and walking to and from school trajectories representing overall physical activity pattern
^f Adjusted for childhood BMIZ at age 7/ 8 or 9 years, birth order, maternal schooling, maternal marital status and SES asset quintile at child age 7/8 years, and sedentary behavior and sleep trajectories

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