FSG screen, with the first endoscopy that then followed brand new T
Participants with a positive baseline FSG screening, diagnostic endoscopy within 6 months from baseline and no cancer findings were invited to complete the interviewer-administered telephone-based Study of Colonoscopy Utilization (SCU) questionnaire. 26 A baseline adenoma was defined as an adenoma found within the first 18 months following a positive T0 0 FSG screen, or on an endoscopy within 6 months of the first endoscopy following the screen. A questionnaire collected information on all known endoscopy after randomisation. Medical record abstraction was performed to verify the collected questionnaire information. Individuals with diagnosed adenoma at baseline but free of adenoma at the second endoscopy were considered controls for this analysis, while individuals with a diagnosis of adenoma at the second endoscopy after resection of adenoma found at baseline were defined as recurrent colorectal adenoma cases. Participants not in SCU but with a positive Tstep 3/5 screen which resulted in an endoscopy that discovered recurrence were also included.
Once further limiting to people just who finished a legitimate BQ (n = 1978), no cancer record prior to BQ (letter = 1894), done DQX (letter = 1784), a legitimate DQX (n = 1742) and you can who had zero cancer tumors records prior to DQX (n = 1741), the final investigation included 855 colorectal metachronous adenoma circumstances and 886 controls.
CRC frequency
More than an average realize-up age of twelve.five years, colorectal cancers chance try ascertained mostly because of shipped Annual Studies Revise Questionnaire and you can constant mailing otherwise telephone just in case you failed to respond. Scientific ideas were used to verify cancer occurrence, stage and you will location. 25 The input arm of PLCO demo was subsequent limited so you’re able to a valid BQ (letter = 75,611), zero history of any cancer tumors just before BQ (letter = 72,151), completed a good DQX (letter = 60,358), keeps legitimate DQX (n = 58,637) no reputation for people cancers just before DQX (letter = 58,535). The new manage arm of PLCO trial try after that limited to a valid BQ (letter = 74,366), zero history of one malignant tumors in advance of BQ (letter = 70,885) with no reputation of any malignant tumors just before DHQ (n = forty two,934). The past investigation included 58,535 sufferers in the intervention arm, out-of who 697 set-up CRC during the follow-right up. The new control arm is actually faster in order to forty-two,934 professionals which have good BQ, DHQ with no cancer record, out-of whom 578 set up CRC while in the pursue-up.
Mathematical data
Conclusion statistics both for continuous (imply ± important deviation) and you can categorical variables (amount and you can %) were used to explain data populations. Person-many years getting CRC frequency try computed on the day off randomisation towards time of CRC analysis, passing, loss-to-follow-upwards, or stop off realize-right up, whichever appeared very first. twenty five
Since information on incident and metachronous adenoma was only collected and confirmed after the T3 or T5 screen, we estimated 5-year risks for incident and metachronous adenomas with odds ratios and corresponding 95% confidence intervals (95% CIs) calculated using multivariable adjusted unconditional logistic regression. Risk for incident CRC was estimated using hazard ratios and corresponding 95% CIs from multivariable adjusted cox-proportional hazard models. Potential confounding factors were selected based on biological plausibility, literature reports and/or ?10% change in relative 
risks. 27 Confounding factors evaluated included age, sex, race, education, recruitment site, family history of CRC, body mass index, smoking status, alcohol consumption, exercise and daily intakes of total energy, vitamin D and magnesium. Tests for trend across categories were performed in regression models by assigning the score j to the jth level of the variable selected.
For primary analysis, calcium intake was categorised as 600 mg/day, 600–1200 mg/day, 1200–1600 mg/day and ?1600 mg/day. Previous studies showed a protective effect of calcium in risk reduction at daily intake levels of calcium from 600 to 1000 mg/day, 28 with no further protection beyond this range. 15,29,30 Almost all participants in our study are 50 years or older. The calcium RDA is 1200 mg/day for women between 51 and 70 years and for all adults aged > 70 years. 31 Thus, 600–1200 mg/day is used as the reference group. The cut-off at 1600 mg/day is the upper quartile in this study. Investigation of associations between calcium intake and all three outcomes were also conducted by strata of Ca:Mg ratios ( 50 is 1200 and 1000 mg for women and men, respectively. All tests were two-sided, and statistical significance threshold was set at 0.05. Statistical analyses were performed using SAS statistical software (version 9.4; SAS Institute, Cary, NC).