Journal of Environmental and Public Health

Research Article

Pilot Study on the Impact of Biogas as a Fuel Source on Respiratory Health of Women on Rural Kenyan Smallholder Dairy Farms

Table 4

Descriptive statistics of spirometry measures for the biogas and referent groups of Kenyan farmwomen.


Variable	Biogas farms (n = 30 women)			Referent farms (n = 31 women)			P value
Variable	Mean	Median	Range	Mean	Median	Range

FVC
Measured	2.6	2.7	1.4, 4.3	2.7	2.6	1.6, 4.1	0.65
Predicted	3.1	3.2	2.1, 5.5	3.0	3.1	2.2, 3.6	0.39
Percent predicted (%)	84	85	49, 114	89	85	51, 131	0.16
FEV₁
Measured	2.3	2.3	1.3, 3.9	2.3	2.3	1.6, 3.1	0.92
Predicted	2.6	2.6	1.8, 4.4	2.5	2.6	1.8, 2.9	0.51
Percent predicted (%)	90	89	61, 120	93	93	60, 117	0.34
PEFR
Measured	5.2	5.0	2.8, 7.4	4.9	4.7	2.9, 8.3	0.28
Predicted	6.1	6.0	4.9, 10	5.9	6.0	5.0, 7.3	0.36
Percent predicted (%)	87	87	47, 120	83	84	47, 133	0.48
FEF
Measured¹	3.2	3.2	1.5, 5.3	3.1	2.9	2.1, 5.8	0.94
Predicted¹	3.5	3.5	2.6, 5.4	3.4	3.4	2.6, 4.0	0.47
Percent predicted (%)	91	95	47, 120	93	88	59, 161	0.78
FEV₁/FVC ratio
Measured	0.90	0.89	0.76, 1.0	0.89	0.90	0.76, 1.0	0.72
Predicted	0.85	0.85	0.83, 0.99	0.86	0.85	0.82, 0.99	0.86
Percent predicted (%)	105	107	90, 117	104	104	88, 120	0.70

¹Parametric tests performed on square root transformed data.
FVC: forced vital capacity; FEV₁: forced expiratory volume at 1 second.
PEFR: peak expiratory flow rate; FEF: forced expiratory flow during the middle 50% of the expiration.
Percent predicted values calculated based on Knudsen reference values for African-American populations.