Questions relating to premenstrual asthma

Table 1 Etiological factors in premenstrual asthma

Group	Factor	Ref.	Design	Level of factor in PMA	Level of factor in non PMA	P vaule	Evidence level1
Hormones	Estrogen	Pasaoglu et al[41]	Pre-post study	PM: 89.3 pg/mL	PM: 72 pg/mL	N/A	4
	Estrogen	Pereira et al[40]	Cross-sectional study	PO: 111.49 pg/mL PM: 95.9 pg/mL	PO: 131.31 pg/mL PM: 123.83	(for change) 0.845	4
	Progesterone	Pasaoglu et al[41]	Pre-post study	PM: 7.3 pg/mL	PM: 9.2 pg/mL	N/A	4
	Progesterone	Pereira et al[40]	Cross-sectional study	PO: 0.83 pg/mL	PO: 1.39 pg/mL	(for change) 0.225	4
				PM: 6.82 pg/mL	PM: 6.31
	Estrogen/	Pereira et al[40]	Cross-sectional study	PO: 219.26 pg/mL	PO: 356.6	0.865	4
	Progesterone			PM: 35.53 pg/mL	PM: 355.22	0.371
	LH	Pasaoglu et al[41]	Pre-post study	PM: 3.5 mU/mL	PM: 4.9 mU/mL	N/A	4
	FSH	Pasaoglu et al[41]	Pre-post study	PM: 13.3 mIU/mL	PM: 3.3 mIU/mL	N/A	4
Inflammation	LTC4	Nakasato et al[19]	Pre-post study	PO: 24.0 pg/mL	PO: NA1	NA	4
				PM: 69.0 pg/mL	PM: NA1
	LTC4	Pereira et al[52]	Cross-sectional study	PO: 1.5 ng/mL	PO: 1.4 ng/mL	NS	4
				PM: 1.31 pg/mL	PM: 1.29
	Prostaglandin F2α	Eliasson et al[53]	Cross-sectional study	Early cycle: 143 pg/0.1 mL	169.3 pg/0.1 mL	NS1	4
				Late cycle: 15.9 pg/0.1 mL	9.5 pg/0.1 mL	NS1
Atopy	Total IgE (geometric mean)	Pereira et al[47]	Cross-sectional study	206.31	87.99	0.01	4
	Total IgE (% > 100 kU/L)	Pereira et al[47]	Cross-sectional study	84	43	0.001	4
	Total IgE (mean)	Rao et al[48]	Cross-sectional study	208.4	292.2	0.06	4
	Phadiatop (% +)	Pereira et al[47]	Cross-sectional study	68	50	0.17	4
	Skin prick test +	Rao et al[48]	Cross-sectional study	60 (76%)	297 (88%)	0.01	4
Others	Aspirin sensitivity	Rao[48]	Cross-sectional study	23 (39%)	36 (10%)	< 0.0001	4
	Use of aspirin or non-steroidal anti-inflammatory drugs	Forbes[58]	Cross-sectional study	14/38 (36.8%)	172/421 (40.9%)	NS	4

¹Oxford Centre for Evidence-based Medicine-Levels of Evidence (March 2009, http://www.cebm.net/oxford-centre-evidence-based-medicine-levels-evidence-march-2009/). N/A: Not available; PMA: Premenstrual asthma; NS: Not significant; LTC: Leukotrienes.