Blastocystis infection in Malaysia: Evidence of waterborne and human-to-human transmissions among the Proto-Malay, Negrito and Senoi tribes of Orang Asli

Table 3 Potential risk factors associated with Blastocystis infection among the overall population studied (univariate analysis, n = 500)

Variables	No. examined	Infected (%)	OR (95% CI)	p-value
Age (years)
<15	221	22.6	1.28 (0.83,1.97)	0.272
≥15	279	18.6	1	0.272
Gender
Female	281	21.7	1.20 (0.77,1.87)	0.411
Male	219	18.7	1	0.411
Drinking untreated water
Yes	232	29.4	2.92 (1.84,4.63)	<0.001^a,b
No	265	12.5	1	<0.001^a,b
Bathing and washing in the river
Yes	143	23.8	1.33 (0.83,2.12)	0.236
No	357	19.0	1	0.236
Not washing hands after playing with soil or gardening
Yes	197	25.0	1.58 (1.02,2.45)	0.040^a
No	303	17.4	1	0.040^a
Presence of domestic animals
Yes	309	20.1	0.96 (0.62,1.49)	0.862
No	191	20.8	1	0.862
Indiscriminate defecation
Yes	192	22.9	1.28 (0.82,1.99)	0.270
No	308	18.8	1	0.270
Sewage disposal
Outdoor	240	22.1	1.22 (0.79,1.87)	0.369
Common drainage	260	18.8	1	0.369
Eating with hands
Yes	328	20.2	0.96 (0.60,1.52)	0.859
No	172	20.9	1	0.859
Consuming raw vegetables
Yes	238	21.1	1.08 (0.70,1.68)	0.717
No	262	19.8	1	0.717
Eating fresh fruits
Yes	395	18.4	0.63 (0.39,1.01)	0.055
No	105	26.4	1	0.055
Father’s education
Non-educated (<6 yrs)	222	24.3	1.47 (0.76,2.83)	0.247
Educated (>6 yrs)	78	17.9	1	0.247
Mother’s education
Non-educated (<6 yrs)	232	25.0	1.93 (0.93,4.03)	0.075
Educated (>6 yrs)	68	14.7	1	0.075
Working mothers
Yes	153	23.8	1.15 (0.67,1.97)	0.625
No	147	21.5	1
Household members
≥8	171	21.6	1.12 (0.71,1.77)	0.621
<8	329	19.8	1	0.621
Household monthly income
<RM500	260	23.5	1.49 (0.96,2.32)	0.077
>RM500	240	17.1	1	0.077
Other family members infected with Blastocystis
Yes	116	50.9	8.21 (5.07,13.30)	<0.001^a,b
No	384	11.2	1	<0.001^a,b

RM = Malaysian Ringgit; (US$100 = RM307.85) [1^st February 2013].
Reference group marked as OR = 1 [OR = Odds Ratio].
CI = Confidence interval.
^a Significant association (p < 0.05).
^b Variables were confirmed by multivariate analysis as significant risk factors.