LucKi Birth Cohort Study: rationale and design

BMC Public Health

Table 3 Baseline characteristics of LucKi participants born between July 2006 and December 2011

	N = 4.230
Sex (% male)	50.2 %
Gestational age at birth^a
• < 37 weeks	5.8 %
• 37–40 weeks	70.7 %
• > 40 weeks	22.9 %
Maternal smoking during pregnancy	10.5 %
Breastfeeding (exclusive or combined)
• until age 3 months	35.4 %
• until age 6 months	16.9 %
Parental history of atopy^b	57.0 %
Number of older siblings^a
• 0	43.2 %
• 1	38.3 %
• > 1	11.9 %
Day care attendance^c	55.2 %
Pet keeping^d	51.4 %
Eczema prevalence^e
Age 7 months	14.7 %
Age 14 months	13.3 %
Age 3 years	16.2 %
Wheeze prevalence^e
Age 7 months	16.4 %
Age 14 months	18.3 %
Age 3 years	13.0 %
Overweight prevalence^f
Age 3 years	7.6 %

^a Due to missing values, percentages do not add up to 100 %
^b Defined as mother or father ever having asthma, hay fever, or eczema
^c Defined as visiting day care weekly at age 7 months of age
^d Defined as ≥ 1 pets in the home at baseline (1–2 weeks of age)
^e The prevalence of eczema and wheeze is based on parentally reported symptoms through validated ISAAC questionnaires [10]
^f The prevalence of overweight was calculated with age- and sex-specific cut-off points for Body Mass Index of a widely used international standard [14]

ISSN: 1471-2458