Physical activity, obesity and sedentary behaviour and the risks of colon and rectal cancers in the 45 and up study

Table 4 Cox proportional hazards of incident rectal cancer according to BMI, sedentary behaviour and types of physical activity

Variable	Events	No person-years	Age-adjusted HR	Multivariable HR⁽¹⁾
BMI Kg/m²
15- < 23.6	93	154,782	1.00	1.00
≥ 23.6- < 26.2	93	150,905	1.03 (0.77–1.37)	0.84 (0.62–1.14)
≥ 26.2- < 29.4	87	156,855	0.92 (0.69–1.24)	0.73 (0.54–1.00)
≥ 29.4-≤50	93	156,110	0.99 (0.74–1.32)	0.76 (0.55–1.04)
Unknown	n.p	3273	1.52 (0.48–4.81)	0.89 (0.22–3.62)
P-value^(a)				0.20
P-trend^(b)				0.12
Sitting hours/day
0- < 3	50	87,149	1.00	1.00
3- < 5	100	167,893	1.04 (0.74–1.46)	1.03 (0.72–1.48)
5- < 8	111	178,263	1.09 (0.78–1.52)	1.10 (0.77–1.57)
8+	72	143,988	0.87 (0.61–1.25)	0.90 (0.61–1.32)
Unknown	36	44,633	1.41 (0.92–2.16)	1.07 (0.66–1.74)
P-value^(a)				0.65
P-trend^(b)				0.40
Moderate activity minutes/week
None	20	30,195	1.00	1.00
> 0–149	77	102,607	0.85 (0.52–1.39)	0.85 (0.51–1.43)
150 or more	252	433,967	0.88 (0.56–1.38)	0.93 (0.57–1.51)
Unknown	20	20,487	1.47 (0.79–2.73)	1.17 (0.57–2.38)
P-value^(a)				0.77
P-trend^(b)				0.21
Vigorous activity minutes/week
None	163	270,375	1.00	1.00
> 0–74	53	102,607	0.86 (0.63–1.17)	0.98 (0.71–1.36)
75 or more	58	145,748	0.66 (0.49–0.89)	0.70 (0.50–0.98)
Unknown	95	103,194	1.52 (1.18–1.96)	1.34 (1.01–1.79)
P-value^(a)				0.11
P-trend^(b)				0.78

⁽¹⁾Multivariable models adjusted for: birth cohort, sex, education, BMI, sitting time, time spent on moderate and vigorous activity, smoking, alcohol, country of birth, guidelines of fruit and vegetables, weekly intake of processed food, red meat and fibre, aspirin use, parental history of CRC and history of colorectal testing
^(a)‘P-value’ for each variable corresponds to a test of whether all HRs = 1
^(b)‘P-trend’ is for test of linear association in the log hazard scale and obtained by substituting the categorical versions of covariates in the Cox model with continuous or ordinal versions where appropriate
‘Unknown’ category was excluded from the estimation of P-values and P-trends
n.p Not publishable because of small number, confidentiality or ethical concerns about the data

ISSN: 1471-2458