Potential risk factors for constipation in the community

Table 3 Income level and constipation

Ref.	Location	Sample size	Age range (yr)	Definition of constipation	Income/year or week	Prevalence (%)	Odds ratio (95%CI)	P value
Stewart et al[68], 1999	United States	10018	> 18	Rome II	< $20000; $20-29900; $30-49900; > $50000	NR	1; 0.90; 1.10; 1.02	NR
Pare et al[45], 2001	Canada	1149	> 18	Self-report (3 mo)	< $20000; $20-39900; $40-59900; $60-79900; > $80000	33.8; 23.7; 24.3; 28.0; 21.8	1.55; 1.01; 1.11; 1.28; 1	NR
Pare et al[45], 2001	Canada	1149	> 18	Rome I	< $20000; $20-39900; $40-59900; $60-79900; > $80000	18.5; 16.3; 17.6; 13.1; 12.1	1.53; 1.35; 1.45; 1.08; 1	NR
Pare et al[45], 2001	Canada	1149	> 18	Rome II	< $20000; $20-39900; $40-59900; $60-79900; > $80000	15.3; 14.3; 13.9; 14.5; 8.3	1.84; 1.72; 1.67; 1.75; 1	NR
Wald et al[61], 2008	United States	2000	> 15	Self-report (12 mo)	Low; Middle; High	20.9; 16.1; 16.8	NR	NR
Wald et al[61], 2008	United Kingdom	2000	> 15	Self-report (12 mo)	Low; Middle;High	8.8; 7.27.1	NR	NR
Wald et al[61], 2008	France	2000	> 15	Self-report (12 mo)	Low; Middle; High	14.9; 11.3; 15.8	NR	NR
Wald et al[61], 2008	Germany	2000	> 15	Self-report (12 mo)	Low; Middle; High	7.2; 3.6; 5.3	NR	NR
Enck et al[75], 2016	Germany	15002	> 18	Self-report (12 mo)	< 1000; 1000-1500; 1500-2000; 2000-2500; 2500-3000; 3000-4000; > 4000	19.01; 18.81; 14.61; 13.61; 13.31; 11.31; 11.51	NR	< 0.001
Wald et al[61], 2008	Italy	2000	> 15	Self-report (12 mo)	Low; Middle; High	7.8; 7.0; 8.4	NR	NR
Wald et al[61], 2008	Brazil	2000	> 15	Self-report (12 mo)	Low; Middle; High	17.9; 15.8; 14.2	NR	NR
Schmidt et al[66], 2016	Brazil	2162	> 18	Rome III	2-15; 1.5-2; 1-1.5; 0.5-1; 0-0.5	11.1; 9.7; 13.8; 15.4; 21.8	1.0; 0.8 (0.5, 1.4); 1.3 (0.8, 2.1); 1.4 (0.9, 2.2); 1.9 (1.2, 3.0)	NR
Wald et al[61], 2008	South Korea	2000	> 15	Self-report (12 mo)	Low; Middle; High	17.1; 15.7; 17.1	NR	NR
Wald et al[59], 2010	Colombia	2000	> 15	Self-report (12 mo)	Low; Middle; High	23.9; 20.3; 14.8	NR	NR
Wald et al[59], 2010	China	2100	15-60	Self-report (12 mo)	Low; Middle; High	16.2; 15.5; 13.2	NR	NR
Wald et al[59], 2010	Indonesia	2000	> 15	Self-report (12 mo)	Low; Middle; High	13.1; 12.2; 14.0	NR	NR
Moezi et al[52], 2018	Iran	9264	40-75	Rome IV	Low; High	9.1; 6.5	NR	0.024
Cheng et al[57], 2003	Hong Kong	3282	18-80	Rome II	Nil; < 10000; 10000-19999; 20000-29999; 30000-39999; 40000-49999; > 50000	13.6; 14.8; 12.5; 12.6; 12.5; 12.5; 13.1	NR	NR
Jun et al[58], 2006	South Korea	1029	> 15	Rome II	< 1000; 1010-2000; 2010-3000; 3010-4000; > 4010	16; 15; 20; 26; 24	NR	0.044
Bytzer et al[82], 2001	Australia	8185	> 18	Rome II	5th quintile (lowest); 4th quintile; 3rd quintile; 2nd quintile; 1st quintile (highest)	10.2; 10.3; 9.6; 8.7; 6.3	NR	NR

¹Calculated from data published.

Note: Income is stated in various currencies. NR: Not reported; NS: Not significant.