1. GRADE Asssessment.

Outcomes No. studies (No. participants)	Study limitations	Inconsistency	Indirectness	Imprecision	Publication bias	GRADE assessment
Calcium intake 1 (75)	Serious limitations (‐1): lack of details on randomisation procedure, and lack of blinding of participants and personnel	n.a.	n.a.	Imprecision (‐1): only one small study	n.a.	++, Low quality
Bone mineral density 1 (275)	No serious limitations	n.a.	n.a.	Imprecision (‐1): only one study	n.a.	+++, Moderate quality
Use of nutrition as health protective behaviour 1 (266)	Serious limitations (‐1): lack of blinding of participants, personnel, and outcome assessors	n.a.	n.a.	Imprecision (‐1): only one study	n.a.	++, Low quality
Junk food intake 1 (266)	Serious limitations (‐1): lack of blinding of participants, personnel, and outcome assessors	n.a.	n.a.	Imprecision (‐1): only one study	n.a.	++, Low quality
Milk consumption 1 (75)	Serious limitations (‐1): lack of details on randomisation procedure, and lack of blinding of participants and personnel	n.a.	n.a.	Imprecision (‐1): only one small study	n.a.	++, Low quality
Calcium supplementation 1 (75)	Serious limitations (‐1): lack of details on randomisation procedure, and lack of blinding of participants and personnel	n.a.	n.a.	Imprecision (‐1): only one small study	n.a.	++, Low quality

n.a. = not applicable