Yosephin 2015.

Study characteristics
Methods	Randomised controlled trial Parallel‐group
Participants	Female workers aged 30–45 years, healthy, married, not pregnant and breastfeeding, not a smoker, not an alcohol drinker, not on a diet and willing to sign ethical informed consent form. The study was conducted in Indonesia.
Interventions	Intervention: 400 IU of vitamin D and 500 mg of calcium Control: 400 IU of vitamin D Trial duration: 12 weeks
Outcomes	Serum 25(OH)D and blood pressure
Notes	More than half of the VDC group subjects (55.0%) had unusual BMI: 15.0% overweight and 40.0% obese. More than two‐thirds of the VD group subjects (78.9%) had unusual BMI; 10.5% overweight and 68.4% obese. The average levels of serum 25(OH)D in the VDC group was 16.7 ng/dL with the highest subject’s serum at 24.9 ng/dL and the lowest at 8.7 ng/dL. The average levels of serum 25 OH)D in the VD group was 14.9 ng/dL with the highest subject’s serum at 22.20 ng/dL and the lowest at 3.5 ng/dL. When the average levels of serum 25(OH)D in both groups were being compared, the difference was not significant (P > 0.05).
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Unclear risk	Double‐blind randomised controlled trial
Allocation concealment (selection bias)	Unclear risk	The research subjects were randomly divided into two treatments in which each treatment consisted of 21 subjects. VDC formulation consisted of 400 IU of vitamin D and 500 mg of calcium, while VD formulation consisted of 400 IU of vitamin D. Each week, both capsule formulae (7 capsules) were transferred into sealed small plastic bags. On each plastic bag, respondents’ names and the type of formula that respondents received were randomised at the beginning of the treatment. Each small plastic bag was delivered to the distribution crew, namely, 2 labour union staff.
Blinding of participants and personnel (performance bias) All outcomes	Low risk	Type of supplement and differences in the composition contained in capsules provided to each woman worker were not known to researchers and distribution crew. Each week, both capsule formulae (7 capsules) were transferred into sealed small plastic bags. On each plastic bag, respondents’ names and the type of formula that respondents received were randomised at the beginning of the treatment. Each small plastic bag was delivered to the distribution crew, namely, 2 labour union staff. Type of supplement and differences in the composition contained in capsules provided to each female worker were not known to researchers and distribution crew. Subjects took the supplement capsules by using drinking water in front of the labour union staff and capsule strip tears were collected in the plastic bags.
Blinding of outcome assessment (detection bias) All outcomes	Unclear risk	Blood pressure measurement was also conducted twice before and after 12‐week supplementation by a physician.
Incomplete outcome data (attrition bias) All outcomes	Low risk	42 research subjects were selected. Each treatment group had 21 subjects, but one of them was pregnant on the VDC group while on the VD group there were 2 subjects who could not complete the intervention due to resigning from the garment factory.
Selective reporting (reporting bias)	Unclear risk	No protocol available
Other bias	Unclear risk	More than half of the VDC group subjects (55.0%) had unusual BMI; 15.0% overweight and 40.0% obese. More than two‐thirds of the VD group subjects (78.9%) had unusual BMI; 10.5% overweight and 68.4% obese.

^{ABP: ambulatory blood pressure
BMI: body mass index
BP: blood pressure
DBP: diastolic blood pressure
HDL: high‐density lipids
ID: Identification
LDL: low‐density lipids
SBP: systolic blood pressure
SD: standard deviation
VD: Vitamin D
VDC:Vitamin D and Calciium}