Trajectories of Physical Activity Predict the Onset of Depressive Symptoms but Not Their Progression: A Prospective Cohort Study

Table 1

Descriptive statistics of the original sample (–3596).

Variables		Measurement year		Mean ± SD/%	Range
Covariates	Age	1980	3596	10.44 ± 4.99	3–18
	Childhood negative emotionality	1980	3177	1.06 ± 0.11	1–2
	Parental education^†	1980	3540	1.90 ± 0.77	1–3
	Parental income	1980	3453	4.80 ± 1.94	1–8
	Symptoms of depression	1992	2330	2.14 ± 0.60	1–4.57
	Symptoms of depression	1997	2099	2.15 ± 0.67	1–4.57
	Symptoms of depression	2001	2097	2.07 ± 0.67	1–4.62
	Symptoms of depression	2007	2056	2.06 ± 0.68	1–4.67
	Participants’ education^‡	2007	2022	2.11 ± 0.90	1–3
	Participants’ income	2007	2146	3.50 ± 1.56	1–8
	Social support	2007	2055	4.15 ± 0.80	1.08–5.00
	Body mass index	2007	2170	26.00 ± 4.75	16.56–58.82
	Smoking status	2007	2224	3.81 ± 1.53	1–5
Physical activity indices	Physical activity	1980	2224	9.05 ± 1.83	5–14
	Physical activity	1983	2116	9.03 ± 1.88	5–14
	Physical activity	1986	2320	8.90 ± 2.01	5–14
	Physical activity	1989	2619	8.63 ± 2.10	5–14
	Physical activity	1992	2192	9.08 ± 1.92	5–14
	Physical activity	2001	2442	8.86 ± 1.96	5–15
	Physical activity	2007	2166	8.81 ± 1.81	5–15
	Physical activity	2011	1910	9.02 ± 1.88	5–15
Physical activity trajectory groups	Lightly physically active	1980–2011	371	10.4%
	Moderately physically active	1980–2011	3046	85.5%
	Highly physically active	1980–2011	147	4.1%
Dependent variable	Symptoms of depression (BDI-II)	2012	1724	5.04 ± 6.60	0–58

The original sample size was 3596, and 1764 (49.1%) of the participants were males and 1832 (50.9%) were females.
^†The frequencies of parents’ educational levels were as follows: low, (34.7%), average, (40.3%), high, and (25.0%).
^‡The frequencies of participants’ educational levels were as follows: low, (35.3%), average, (18.6%), high, and (46.1%).
Physical activity indices ≤ 7 indicate low, >7 to 10 < moderate, and ≥10 high levels of physical activity. Factors scores, which were predicted from physical activity indices (1980–2011) (see Supplementary Table  3), were used in LCGA.