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. 2012 Dec 12;2012(12):CD008650. doi: 10.1002/14651858.CD008650.pub2

Kajimoto 2005.

Methods This study was a double‐blind, placebo‐controlled randomised trial with a 3‐arm parallel design, with a low‐dose treatment to high‐dose treatment to control randomisation ratio of 1:1.015:0.97
Participants INCLUSION CRITERIA:

  • BMI 22.5 to 30 kg/m2


EXCLUSION CRITERIA:

  • taking medications or health foods that may affect lipid metabolism

  • history of food allergy

  • 200 mL of blood withdrawn within 1 month or 400 mL withdrawn within 3 months

  • judged to be inappropriate by study investigator


DIAGNOSTIC CRITERIA:

  • height (measured without shoes to nearest 0.1 cm)

  • weight (measured without shoes or heavy outer clothing, recorded to the nearest 0.1 kg using a scale (Tanita TBF‐614, Tanita, Tokyo, Japan)
Interventions NUMBER OF STUDY CENTRES: NR
COUNTRY/ LOCATION: Japan
SETTING: NR
TREATMENT BEFORE STUDY: 2‐week run‐in period
Outcomes OUTCOME(S) (as stated in the protocol/registered trial documents):
PRIMARY OUTCOME(S): unknown
SECONDARY OUTCOME(S): unknown
OTHER OUTCOME(S): unknown
Study details STUDY TERMINATED BEFORE REGULAR END: no
Publication details This study was published in English in the Journal of Health Science, a peer‐reviewed journal, and no sources of support were declared by the authors
Stated aim of study Quote from study: "in the present study, we investigated the effectiveness of 12 week consumption of a tea catechin‐containing drink with a little caffeine on body fat reduction and evaluated its safety in healthy adult men and women showing 22.5<body mass index (BMI)≤30kg/m2"
Notes We contacted the authors to ask if this trial was randomised, and received an affirmative reply
BMI: body mass index; NR: not reported
Risk of bias
Bias Authors' judgement Support for judgement
Random sequence generation (selection bias) Unclear risk Quote from study: "the subjects were divided into 3 groups based on the results of the preliminary screening so that the three groups were uniform in background, including age, BMI and waist/hip ratio."
Comment: contact with authors confirmed that the study was randomised; however, the method of randomisation was not reported  
Allocation concealment (selection bias) Unclear risk Comment: not reported
Blinding of participants and personnel (performance bias) 
 All outcomes Unclear risk Quote from study: "we conducted a double‐blind study with three parallel arms"
"Prior to initiation of the study, it was confirmed that the catechin drink could not be distinguished from the placebo drink by flavour, taste or packaging"
Comment: no mention of effectiveness of blinding efforts. No mention of whether researchers and staff were blinded to study components
Blinding of outcome assessment (detection bias) 
 All outcomes Low risk Comment: all outcomes on which the study reported were objective and measured by assessors. Therefore, whether or not assessors were blinded, risk of detection bias was assessed as low
Incomplete outcome data (attrition bias) 
 All outcomes Low risk Comment: authors adequately accounted for attrition
Selective reporting (reporting bias) Low risk Comment: all outcome measurements stated in methods section were reported in the results
Other bias Unclear risk Comment: study drink produced by ITOEN Ltd, and 1 of the authors was employed by ITOEN Ltd.; nature of corporate support for study was unclear. Results were positive so we judged that there was an unclear risk of bias