Fecal microbes, short chain fatty acids, and colorectal cancer across racial/ethnic groups

Table 1 Participant characteristics n (range or %)

Characteristic	AA	AI	Hispanic	White	All groups
Age, mean (range)12	61.8 (50-72)	59.4 (50-75)	54.4 (50-59)	63.8 (57-74)	59.9 (50-75)
Age group, yr
50-59	2	3	5	1	11 (55)
60-69	1	1	0	3	5 (25)
70-79	2	1	0	1	4 (20)
BMI, mean ± SD12	33.6 ± 7.7	29.8 ± 4.4	32.2 ± 8.2	34.8 ± 4.0	32.7 (22.8-43.9)
Sex
Male	1	2	2	1	6 (30)
Female	4	3	3	4	14 (70)
Marital status3
Married	4	4	3	2	13 (65)
Widowed	0	1	1	1	3 (15)
Never married/other	1	0	1	2	4 (20)
Education level4
Some high school and below	0	0	2	0	2 (10)
High school grad/GED	0	0	3	0	3 (15)
Some college or tech school	2	3	0	4	9 (45)
College grad and above	3	2	0	1	6 (30)
Insurance5
Yes	4	4	1	4	14 (70)
No	1	1	4	1	6 (30)

¹By one-way ANOVA, there was no statistically significant difference among racial/ethnic groups in age (P = 0.319) or BMI (P = 0.649);

²By independent samples t test, there was no statistically significant difference between African Americans and others in age or BMI;

³By χ² with Fisher’s exact test, there was no significant difference in marital status across racial/ethnic groups or between African Americans and others;

⁴By χ² with Fisher’s exact test, there was a statistically significant difference in education level among the racial/ethnic groups (P = 0.008). There was no significant difference in education level between African Americans and others;

⁵By χ² with Fisher’s exact test, there was no significant difference in insurance status across racial/ethnic groups or between African Americans and others. AA: African Americans; AI: American Indians.

Table 2 Backwards stepwise regression identifies relationships between short chain fatty acids and bacterial levels measured by comprehensive stool analysis

Variables	B	P value
Total SCFAs (D)
Clostridium (I)	-3.164	0.0191
Acetate (D)
Clostridium (I)	-2.294	0.0011
Butyrate (D)
Bacteroides (I)	0.347	0.0271
Clostridium (I)	-0.880	0.0121

¹Statistically significant difference detected among or between groups. (D): Dependent variable; (I): Independent variable.

Table 3 Dietary intake by race/ethnicity and by African Americans vs all others

Food frequency question	Percent reporting “daily” intake (frequency) or≥4 servings/d (servings)				Race/ethnicityP value1	AA or all othersP value1
	AA	AI	Hispanic	White
Frequency2
Vegetables	100	0	40	80	0.0034	0.205
Fruit	80	40	40	40	0.664	0.736
Cultured Food	0	20	20	40	0.450	0.128
Foods with probiotics	0	0	20	0	0.0474	1.000
Servings3
Vegetables	40	0	0	0	0.375	0.0274
Fruit	40	0	0	0	0.119	0.0314

¹χ², Fisher’s exact test;

²Frequency responses were the following: daily, weekly, monthly, rarely, never. All responses were included in the analyses;

³Servings responses were the following and were requested per day: none, 1, 2-3, 4 or more. All responses were included in the analyses;

⁴Statistically significant difference detected among or between groups. AA: African Americans; AI: American Indians.