Gawecka 2008.

Study characteristics
Methods	Single centre study done at NICU of Medical Academy Neonatology Department in Warsaw, Poland in 44 preterm infants. Study enrolment: March 2004 to September 2005. I. Allocation Concealment ‐ yes II. Blinding of intervention ‐ yes III. Blinding of outcome measurement(s) ‐ yes IV. Complete follow‐up ‐ yes
Participants	Inclusion criteria: preterm infants < 32 week gestation with a birth weight of < 1500 g, admitted to ICU on day 1 and requiring PN. Exclusion criteria: Severe malformations, metabolic disease, congenital infection with positive blood culture, enteral calories > 25%.
Interventions	Infants received either (initially 44 infants at the enrolment stage): 1) 20% ClinOleic® (n = 18) OR 2) soybean‐based LE, 20% Ivelip® (n = 20) PN protocol: PN started on day 1 with amino acids. The LE was started within 72 hours of life from a dose of 1 g/kg/day and was increased to the maximal dose of 3‐3.5 g/kg/day. Lipids were infused continuously over 24 hours. Blood sampling was done at baseline and after 14 days of lipid infusion. Follow up: All infants were followed up till discharge.
Outcomes	Primary outcome: Tumour necrosis factor–α, IL‐6, and IL‐10 synthesis in un‐stimulated and anti‐CD3 induced peripheral blood mononuclear cells of parenterally fed premature infants. Secondary outcomes: Incidence of BPD, ROP, NEC, IVH, and nosocomial infections in the two groups.
Notes	Study showed no difference in the inflammatory cytokines or clinical parameters in the two groups. LDL cholesterol was significantly higher in olive oil group. No funding source has been mentioned.
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Unclear risk	Quote: "The randomisation was done by a hospital pharmacist." Comment: Details of random sequence generation have not been provided.
Allocation concealment (selection bias)	Low risk	Quote: "Investigators, parents, and nursing staff were unaware of the treatment allocation," "The randomisation was done by a hospital pharmacist." Commnets: Probably done.
Incomplete outcome data (attrition bias) All outcomes	Low risk	Comment: Of the 44 recruited infants, 38 (87%) completed the study, 18 in the olive oil group and 20 in the soy oil group. 2 deaths occurred in each group due to pulmonary complications (balanced in two groups and for the same reason). Two more infants were excluded but the group allocation was not mentioned. Intention to treat analysis was not done. Authors' consensus was that material risk of bias was probably low.
Selective reporting (reporting bias)	Unclear risk	Comment: The protocol for the study was not available to us so we cannot ascertain any deviation from the protocol. The study report did not provide data on IVH (mentioned as not significantly different in the two groups).
Other bias	Low risk	None identified.
Blinding of participants and personnel (performance bias) All outcomes	Low risk	Quote: "randomised with double‐blind method," "randomisation code was broken after the data analysis was performed." "The parenteral lipid emulsion was prepared by the pharmacist." "fat emulsion was administered in a syringe with 'lipids'" (from the article in Polish). Comment: Probably done.
Blinding of outcome assessment (detection bias) All outcomes	Low risk	Quote: "randomisation code was broken after the data analysis was performed" Comment: Probably done.