Table 2 Multivariable Cox proportional hazards regression on the association between childhood and adolescence factors and multiple sclerosis

Sex

 Female

Ref

 Male

0.48

0.41 – 0.56

Number of siblings

 Only child

Ref

 1-2 sibling(s)

0.93

0.73 – 1.17

 ≥ 3 siblings

0.81

0.61 – 1.09

Premature birth (> 4 weeks before due date)

 No

Ref

 Yes

0.94

0.61 – 1.47

Cesarean section

 No

Ref

 Yes

1.10

0.80 – 1.52

Birth weight

 Low

0.99

0.74 – 1.33

 Average

Ref

 High

1.14

0.90 – 1.45

Ever breastfed

 No

Ref

 Yes, ≤ 4 months

1.02

0.79 – 1.31

 Yes, > 4 months

0.88

0.69 – 1.11

Contact with pets and/or livestock during childhood

 No

Ref

 Yes

1.04

0.69 – 1.58

Attended daycare

 No

Ref

 Yes, 1st attendance at age 3-6 years

0.93

0.77 – 1.12

 Yes, 1st attendance at age 1- < 3 year(s)

0.77

0.58 – 1.03

 Yes, 1st attendance at age < 1 year

0.97

0.63 – 1.50

Weight at the age of 10 years compared to peers

 Lower

0.86

0.70 – 1.05

 Average

Ref

 Higher

0.93

0.73 – 1.19

BMI^b at the age of 18 years (kg/m²)

 Underweight (< 18.5)

1.12

0.89 – 1.42

 Normal weight (18.5 - < 25)

Ref

 Overweight (25 - < 30)

2.03

1.41 – 2.94

 Obesity (≥ 30)

1.89

1.02 – 3.48

Childhood Trauma^c (per 5 units)

1.08

0.95 – 1.24