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. Author manuscript; available in PMC: 2020 Oct 22.
Published in final edited form as: J Epidemiol Community Health. 2018 Aug 12;72(12):1076–1082. doi: 10.1136/jech-2018-210809

Table 3.

HR and 95%CIs for the Association between Plasma Vitamin C Concentrations and Risk of Different Causes of Deaths in the Sub-cohort of Linxian General Population Nutrition Intervention Trial, China, 1999-2016

Causes of Deaths Plasma vitamin C
No. of cases Quartilea, crude HRb Quartilea, adjusted HRc Continuousd
HR 95% CI Global Pe Ptrendf HR 95% CI Global Pe Ptrendf HR 95% CI
All deaths Q1 170 1.00 <0.0001 <0.0001 1.00 0.04 0.006 0.90 0.82-0.99
Q2 139 0.79 0.63-0.99 0.91 0.73-1.14
Q3 125 0.65 0.52-0.82 0.76 0.60-0.96
Q4 117 0.60 0.48-0.76 0.75 0.59-0.95
Cancer Q1 52 1.00 0.002 0.007 1.00 0.04 0.08 0.93 0.78-1.12
Q2 29 0.54 0.34-0.85 0.63 0.40-1.00
Q3 26 0.45 0.28-0.71 0.53 0.33-0.85
Q4 34 0.59 0.38-0.90 0.72 0.46-1.13
UGI cancer Q1 37 1.00 0.0004 0.009 1.00 0.04 0.08 0.87 0.70-1.08
Q2 23 0.61 0.36-1.02 0.71 0.42-1.20
Q3 14 0.34 0.18-0.62 0.40 0.21-0.74
Q4 24 0.58 0.35-0.97 0.73 0.43-1.24
non-UGI Cancer Q1 16 1.00 0.2 0.3 1.00 0.3 0.5 1.07 0.78-1.45
Q2 6 0.36 0.14-0.92 0.42 0.16-1.08
Q3 12 0.67 0.32-1.41 0.79 0.37-1.69
Q4 10 0.55 0.25-1.22 0.68 0.30-1.52
Stroke Q1 51 1.00 0.1 0.02 1.00 0.5 0.2 0.91 0.77-1.08
Q2 42 0.81 0.54-1.22 0.93 0.62-1.41
Q3 45 0.79 0.53-1.18 0.92 0.61-1.38
Q4 32 0.57 0.37-0.89 0.72 0.46-1.13
Heart Diseases Q1 50 1.00 0.03 0.003 1.00 0.1 0.03 0.83 0.71-0.98
Q2 50 0.96 0.65-1.41 1.09 0.74-1.62
Q3 41 0.72 0.48-1.09 0.80 0.53-1.22
Q4 33 0.54 0.35-0.85 0.65 0.41-1.02
Other Q1 17 1.00 0.7 0.6 1.00 0.7 0.9 0.94 0.72-1.22
Q2 18 1.00 0.52-1.95 1.20 0.62-2.35
Q3 13 0.68 0.33-1.41 0.82 0.39-1.70
Q4 18 0.92 0.48-1.79 1.17 0.60-2.31

Abbreviation: UGI, upper gastrointestinal cancers including esophageal and gastric cancers.

a

Plasma Vitamin C quantile concentration (in μmol/L) of the sub-cohort by season-specific quartiles (winter/spring): Q1: <34.8/9.1; Q2: 34.8-51.5/9.1-16.8; Q3:51.5- 62.3/16.8-32.2; Q4: >62.3/32.2.

b

These models were adjusted for season of blood draw through stratification.

c

These models were adjusted for 4 age- / sex- subgroups, tobacco smoking, and season of blood draw through stratification.

d

Continuous, define as per 20 μmol/L increases, models were adjusted for 4 age- / sex- subgroups, tobacco smoking, and season of blood draw through stratification.

e

, Global P was derived from the 3 df test for the overall quartile Cox model.

f

, P for trend was derived from the models by assigning each person the ordinal value of the quartile.