Table 1 Demographic information of covariates among children with (case) and without (control) doctor-diagnosed pneumonia (n = 1,510)

Total

1,510

(100.0)

699

(46.3)

811

(53.7)

—

Sex

< 0.001

 Boys

865

(57.3)

436

(50.4)

429

(49.6)

 Girls

645

(42.7)

263

(40.8)

382

(59.2)

Age (years)

< 0.001

 < 1

402

(26.6)

334

(83.1)

68

(16.9)

 = 1

323

(21.4)

130

(40.2)

193

(59.8)

 > 1

785

(52.0)

235

(29.9)

550

(70.1)

Birth season

0.048

 Spring

342

(22.6)

138

(40.4)

204

(59.6)

 Summer

392

(26.0)

184

(46.9)

208

(53.1)

 Autumn

422

(27.9)

197

(46.7)

225

(53.3)

 Winter

354

(23.4)

180

(50.8)

174

(49.2)

Parity

0.046

 1st

1,025

(67.9)

454

(44.3)

571

(55.7)

 2nd – 5th

478

(31.7)

238

(49.8)

240

(50.2)

Gestational age (weeks)

< 0.001

 < 37

92

(6.1)

62

(67.4)

30

(32.6)

 ≥ 37

1,418

(93.9)

637

(44.9)

781

(55.1)

Mode of delivery

< 0.001

 Natural labour

863

(57.2)

360

(41.7)

503

(58.3)

 Caesarean birth

641

(42.5)

333

(52.0)

308

(48.0)

Parental atopy

< 0.001

 No

1,432

(94.8)

646

(45.1)

786

(54.9)

 Yes

78

(5.2)

53

(67.9)

25

(32.1)