Canadian federal penitentiaries as obesogenic environments: a retrospective cohort study

Article Figures & Tables

Table 1:

Sociodemographic factors for all participants

Factor	No. (%) n = 1420
Sex
Male	1276 (89.9)
Female	144 (10.1)
Age, yr
18 to ≤ 24	104 (7.3)
≥ 25 to ≤ 34	389 (27.4)
≥ 35 to ≤ 44	315 (22.2)
≥ 45 to ≤ 64	504 (35.5)
≥ 65	108 (7.6)
Region
Atlantic	520 (36.6)
Ontario	900 (63.4)
First language
English	1265 (89.1)
French	155 (10.9)
Ethnicity
White	904 (63.7)
Black	203 (14.3)
Aboriginal	214 (15.1)
Other	99 (7.0)
Feeding system
Tray (menu)	393 (27.7)
Cafeteria (menu)	522 (36.8)
Kitchenette (no menu)	505 (35.6)
Security level
Maximum	348 (24.5)
Medium	781 (55.0)
Minimum	291 (20.5)
Length of incarceration at follow-up
≤ 18 mo	553 (38.9)
> 18 mo to ≤ 5 yr	458 (32.3)
> 5 yr	409 (28.8)
Length of sentence, yr
2 to ≤ 3	285 (20.1)
> 3 to ≤ 5	286 (20.1)
> 5 to ≤ 25	365 (25.7)
> 25	484 (34.1)

Table 2:

Categories of body mass index for Canadian inmates on admission and at follow-up

Category	BMI range	Admission, no. (%) n = 1420	Follow-up, no. (%) n = 1420	p value
Underweight	< 18.5	17 (1.2)	F	< 0.0001^*
Normal	18.5–24.9	466 (32.8)	222 (15.6)
Overweight	25.0–29.9	559 (39.4)	551 (38.8)
Obese	≥ 30.0	378 (26.6)	645 (45.4)
Overweight and obese	≥ 25	937 (66.0)	1196 (84.2)
Obesity class I	30.0–34.9	236 (16.6)	405 (28.5)
Obesity class II	35.0–39.9	92 (6.5)	146 (10.3)
Extreme obesity class III	≥ 40.0	50 (3.5)	94 (6.6)

Note: BMI = body mass index, F = proportion too low to report and could threaten confidentiality.
↵* χ² test; p < 0.05 considered significant.

Table 3:

Median change in weight and body mass index, and annual rate of change, between admission and follow-up by sociodemographic characteristic

Characteristic	Median weight change, kg (95% CI)	p value^*	Median BMI change (95% CI)	p value^*	Median annual rate of change, kg/yr (95% CI)	p value^*
Overall	+6.20 (5.55–6.85)		+2.00 (1.79–2.21)		+1.52 (1.24–1.81)
Sex
Male	+6.50 (5.82–7.18)	0.3	+2.00 (1.78–2.22)	0.7	+1.46 (1.18–1.75)	0.2
Female	+5.80 (3.60–8.00)	0.3	+2.00 (1.19–2.81)	0.7	+2.69 (0.99–4.39)	0.2
Age, yr
18 to ≤ 24	+4.70 (2.99–6.41)	0.05	+1.60 (1.04–2.16)	0.04	+3.51 (2.08–4.93)	< 0.0001
≥ 25 to ≤ 34	+5.70 (4.62–6.78)		+1.80 (1.45–2.15)		+2.30 (1.63–2.98)
≥ 35 to ≤ 44	+6.30 (4.99–7.70)		+2.00 (1.55–2.45)		+2.13 (1.35–2.92)
≥ 45 to ≤ 64	+7.60 (6.35–8.85)		+2.50 (2.09–2.91)		+1.03 (0.68–1.39)
≥ 65	+5.30 (3.87–9.46)		+1.75 (1.28–3.10)		+0.51 (0.16–0.85)
Region
Atlantic	+5.05 (4.00–6.10)	0.0004	+1.70 (1.35–2.05)	0.002	+1.42 (0.91–1.92)	0.1
Ontario	+7.10 (6.28–7.92)	0.0004	+2.30 (2.04–2.56)	0.002	+1.57 (1.22–1.92)	0.1
First language
English	+6.30 (5.61–6.99)	0.3	+2.00 (1.78–2.22)	0.4	+1.50 (1.20–1.80)	0.9
French	+6.00 (4.08–7.92)	0.3	+1.90 (1.28–2.52)	0.4	+1.75 (0.78–2.72)	0.9
Ethnicity
White	+6.30 (5.47–7.13)	0.004	+2.00 (1.73–2.27)	0.005	+1.42 (1.07–1.78)	0.06
Black	+7.00 (5.54–8.46)		+2.20 (1.75–2.65)		+2.06 (1.22–2.90)
Aboriginal	+7.70 (6.92–10.52)		+2.40 (1.83–2.97)		+1.72 (0.89–2.54)
Other	+3.30 (1.61–4.99)		+1.00 (0.77–1.86)		+1.14 (0.49–1.78)

Note: BMI = body mass index, CI = confidence interval.
↵* Wilcoxon test was used in analyses with two categories (sex, region, language), a Kruskal–Wallis test was used in analyses with three or more categories (age and ethnicity); p < 0.05 was considered significant.

Table 4:

Median change in weight and body mass index, and annual rate of change, between admission and follow-up by institutional characteristic

Characteristic	Median weight change in kg (95% CI)	p value^*	Median BMI change (95% CI)	p value^*	Median annual weight change in kg/yr (95% CI)	p value^*
Overall	+6.20 (5.55–6.85)		+2.00 (1.79–2.21)		+1.52 (1.24–1.81)
Feeding system
Tray (menu)	+6.00 (4.83–7.17)	0.97	+1.90 (1.52–2.28)	0.97	+1.48 (0.98–1.97)	0.97
Cafeteria (menu)	+6.85 (5.75–7.95)		+2.20 (1.86–2.54)		+1.63 (1.18–2.08)
Kitchenette (no menu)	+6.50 (5.41–7.59)		+2.10 (1.74–2.46)		+1.50 (0.93–2.07)
Security level
Maximum	+5.55 (4.32–6.78)	0.05	+1.80 (1.42–2.18)	0.04	+1.45 (0.94–1.95)	0.1
Medium	+7.00 (6.10–7.90)		+2.30 (2.01–2.59)		+1.79 (1.39–2.19)
Minimum	+5.55 (4.07–6.93)		+1.80 (1.34–2.26)		+1.02 (0.24–1.81)
Length of incarceration at follow-up
≤ 18 mo	+5.60 (4.70–6.50)	0.001	+1.90 (1.60–2.20)	0.001	+6.40 (5.33–7.47)	< 0.001
> 18 mo to ≤ 5 yr	+5.75 (4.65–6.85)		+1.80 (1.45–2.15)		+2.09 (1.67–2.51)
> 5 yr	+8.40 (6.92–9.88)		+2.70 (2.23–3.17)		+0.64 (0.54–0.74)
Length of total sentence, yr
2 to ≤ 3	+6.00 (4.63–7.37)	0.006	+2.00 (1.55–2.45)	0.007	+6.21 (4.76–7.66)	< 0.001
> 3 to ≤ 5	+6.25 (4.99–7.51)		+2.00 (1.60–2.40)		+3.74 (2.78–4.70)
> 5 to ≤ 25	+5.50 (4.35–6.65)		+1.70 (1.33–2.07)		+1.95 (1.44–2.46)
> 25	+7.70 (6.36–9.04)		+2.50 (2.06–2.94)		+0.69 (0.56–0.81)

Note: BMI = body mass index, CI = confidence interval.
↵* Kruskal–Wallis test; p < 0.05 was considered significant. The mean (± standard deviation) length of time between admission and follow-up was 5.0 (± 8.3) years.