Lijnen 1995

Methods	Double‐blind, placebo‐controlled parallel‐group cross‐over study. The trial was conducted in Belgium.
Participants	32 male participants. Age: 24 ± 1 (range 20 ‐ 44 years) and weight 75.9 ± 1.3 kg.
Interventions	Intervention group: 1 g elemental calcium as calcium gluconate powder twice a day (morning and evening). Control group: placebo with the same orange flavour as intervention. Trial duration: 16 weeks.
Outcomes	Blood pressure recorded in standing position Intracellular cationic concentrations Transmembrane cation transport systems Plasma total and ionised calcium Calciotropic hormones
Notes	This study was supported by Boehringer Ingelheim.
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Unclear risk	Not described
Allocation concealment (selection bias)	Unclear risk	Not described
Blinding of participants and personnel (performance bias) All outcomes	Low risk	A double‐blind placebo‐control parallel‐group. The calcium supplement and placebo were both orange flavour.
Blinding of outcome assessment (detection bias) All outcomes	Unclear risk	Not described
Incomplete outcome data (attrition bias) All outcomes	Low risk	All participants randomised were included in the results.
Selective reporting (reporting bias)	Low risk	Primary outcomes results were reported.
Other bias	Low risk	Baseline characteristics were similar between calcium and placebo groups.