Short-term and long-term effect of nutrition intervention in the Linxian Dysplasia Nutrition Intervention Trial and the reason for disappearance of the intervention effect: A cohort study.

BACKGROUND: The objective of this study was to determine the short-term and long-term effects of a nutrition intervention in using 37 years of follow-up data. METHODS: The Linxian Dysplasia Population Nutrition Intervention Trial was a randomized, double-blind, placebo-controlled trial with 7 years of intervention and 30 years of follow-up. The Cox proportional hazard model was used for analyses. Subgroup analyses were conducted in age and sex subgroups, and the 30 years of follow-up were divided into two 15-year early and late periods. RESULTS: The results at 37 years did not indicate any effects on mortality from cancers or other diseases. In the first 15 years, the intervention decreased the overall risk of gastric cancer deaths in all participants (hazard ratio [HR], 0.76; 95% confidence interval [CI], 0.58-1.00) and in the subgroup participants younger than 55 years (HR, 0.64; 95% CI, 0.43-0.96). In addition, in the group younger than 55 years (HR, 0.58; 95% CI, 0.35-0.96), the intervention decreased the risk of death from other diseases; and, in the group aged 55 years and older (HR, 0.75; 95% CI, 0.58-0.98), the intervention reduced the risk of death from heart disease. There were no significant results in the later 15 years, which indicated the disappearance of the intervention effect. Comparing demographic characteristics between those who died during the two periods, the participants who died later included more women, had a higher education level, had a lower smoking rate, were younger, and also more had a mild degree of esophageal dysplasia, representing a better lifestyle and health condition. CONCLUSIONS: Long-term follow-up indicated no effect of nutrition on deaths in a population with esophageal squamous dysplasia, further supporting the significance of continuous nutritional intervention for cancer protection. The pattern of protective effect of a nutrition intervention on gastric cancer in patients with esophageal squamous dysplasia was similar to that in the general population. Participants who died in the later period had more protective factors than those who died in the earlier period, contributing to the obvious effect of the intervention in early stage disease.

The Association Between Family History of Upper Gastrointestinal Cancer and the Risk of Death from Upper Gastrointestinal Cancer-based on Linxian Dysplasia Nutrition Intervention Trial (NIT) Cohort.

Objective: Explore the influence of family history of upper gastrointestinal (UGI) cancer on UGI cancer death, based on the Linxian Dysplasia Nutrition Intervention Trial (NIT) cohort. Methods: Family history of UGI cancer was defined as at least one first-degree relative (parent, child, or sibling) had a history of esophageal or gastric cancer. Cancer death was carried out by ICD-10 code. Family history information was collected at baseline and cancer deaths were assessed at each annual follow-up. The COX proportional risk model was used to estimate the hazard ratio (HR) and 95% confidence interval (95% CI). We compared the positive family history group with the negative to determine the risk of family history on UGI cancer death. The effect of category of relatives, number of relatives with UGI cancer, and diagnosis age of relatives on the UGI death risk were further analyzed. Interaction and stratification analyses were done to see the subgroup effects. Sensitivity analyses were also conducted by exclusion of individuals who were followed up less than three years. We considered controlling of covariates including: gender, age (continuity), community, education level, number of siblings (continuity), BMI (continuity), smoking, alcohol use, fresh fruit intake, fresh vegetable intake, hot beverage intake, edible oil intake, meat intake, and moldy staple food intake. All food intake variables were converted into categorical variables. Results: From1985 to2015, we followed up total 3,318 individuals with 898 UGI cancer deaths (537 from ESCC, 77 from GNCC, and 284 from GCC). In a single factor analysis, family history of UGI cancer increased the risk of death of esophageal squamous cell carcinoma (ESCC) by 27% (HR=1.270, 95%CI1.072-1.504). No associations were observed in gastric cardia carcinoma (GCC) and gastric non-cardia carcinoma (GNCC). After adjusting for multi-factor, a family history of UGI cancer risk of death increased by 31.9% from ESCC (HR=1.319,95%CI:1.110-1.567). Subgroup analysis of different types of relatives with UGI cancers, UGI cancers in the mother (HR=1.457,95%CI:1.200-1.768), brother (HR=1.522,95%CI:1.117-2.073), and sister (HR=1.999,95%CI:1.419-2.817) were independent risk factors for ESCC death, while the father was not. In addition, 2 relatives with UGI cancer (HR=1.495, 95%, CI:1.110-2.013) and ≥3 relatives with UGI cancer (HR=2.836, 95%CI:1.842-4.367) significantly increased the risk of ESCC death, and the trend test was statistically significant (P<0.001). Relatives' diagnostic age of 51-60 years (HR=1.322, 95%CI:1.046-1.672) and 41-50 years (HR=1.442, 95%CI:1.078-1.930) were the risk factors for ESCC death, with statistical significance in the trend test (P=0.010). No statistically significant result of the family history effect on the risk of death from GCC or GNCC was found. Sensitivity analysis of 80% of subjects, randomly selected, did not change the results. Conclusion: A family history of UGI cancer may predict the risk of death from ESCC but not from GCC or GNCC. UGI cancer in the mother may predict the risk of death from ESCC, but not father, which indicates gender differences. Gender and smoking are the interaction items with family history in a similar extent. In the subgroup, the risk of ESCC death is more distinct by family history in younger, female, and better-lifestyle individuals, which indicates the unique role of genetic factors.