Table 2. Odds ratio (OR) and its 95% Confidence Interval (95%CI) for allergic symptom development.

	OR	95% CI			P value
Vitamin D deficiency a	1.33	1.07	–	1.64	.009
IgE to cedar pollen (per class increase)	1.28	1.21	–	1.35	< .001
IgE to house dust mite (per class increase)	1.10	1.03	–	1.18	.008
Age (compared with >40 years)
<20 years	0.81	0.19	–	3.55	.781
20–25 years	1.82	1.01	–	3.27	.046
25–30 years	1.49	0.95	–	2.35	.085
30–35 years	1.62	1.04	–	2.53	.034
35–40 years	1.47	0.93	–	2.32	.103
BMI before pregnancy (compared with >25)
<18	1.00	0.68	–	1.47	.995
18–25	1.14	0.82	–	1.60	.436
Family income (per 20,000 increase)	0.95	0.87	–	1.01	.113
Smoking status of subjects (Compared with current smoker)
Never smoker	0.98	0.54	–	1.79	.957
Stopped before pregnancy	1.12	0.61	–	2.07	.708
Stopped after pregnancy	1.04	0.54	–	1.97	.915
Smoking status of subjects’ partners (Compared with current smoker)
Never smoker	1.01	0.81	–	1.26	.940
Stopped before pregnancy	1.01	0.81	–	1.25	.956
Stopped after pregnancy	0.51	0.29	–	0.90	.020
Location (Compared with Kyoto)
Toyama	0.99	0.81	–	1.21	.920
Tottori	1.03	0.80	–	1.34	.795

Adjusted by desert dust, pollen counts, SO₂, humidity, lowest temperature of the day, temperature difference within the day, and month on the day.

Vitamin D deficiency was defined as serum 25(OH)D level < 20 ng/mL on serum samples taken within 3 months before the symptom response.

IgE class to cedar pollen and IgE class to house dust mite were treated as ordered categorical. The OR per one class increase for each is shown.

Age was categorized into 6 groups by 5 years and was treated as categorical.

BMI before pregnancy was categorized into 3 groups, and was treated as categorical.

Family income was categorized into 6 groups and was treated as ordered categorical.