Reported Amount of Salt Added to Food Is Associated with Increased All-Cause and Cancer-Related Mortality in Older Men in a Prospective Cohort Study

Adding salt to foods and hazards of microvascular, cerebrovascular and cardiovascular diseases

BACKGROUND

We aimed to examine the association of the frequency of adding salt to foods and the hazards of the incidence and mortality risks for a range of vascular outcomes, including microvascular, cerebrovascular, and cardiovascular diseases.

METHODS

438,307 participants from the UK Biobank who completed the questionnaire on the frequency of adding salt to foods and were free of vascular disease at baseline were enrolled. Information on the frequency of adding salt to foods (do not include salt used in cooking) was collected at baseline through a touch-screen questionnaire. The primary outcomes included incident microvascular diseases, cerebrovascular diseases, and cardiovascular diseases, respectively. The secondary outcomes included: (1) each component of these vascular diseases (10 components in total), (2) first occurrence of fatal and non-fatal vascular diseases.

RESULTS

During a median follow-up of 12.1 years, a total of 17,169 (3.9%), 10,437 (2.4%), and 48,203 (11.0%) participants developed microvascular, cerebrovascular and cardiovascular diseases, respectively. Overall, the hazards of incident microvascular, cerebrovascular and cardiovascular diseases increased with the increasing frequency of adding salt to foods (all P for trend <0.001). Similar trends were found for the secondary outcomes. Moreover, the positive association of always adding salt to foods with hazard of cardiovascular diseases was stronger among current-smokers (P-interaction = 0.010), younger participants (P-interaction <0.001), and those with lower body mass index levels (P-interaction = 0.003).

CONCLUSIONS

Higher frequency of adding salt to foods was associated with higher hazards of non-fatal and fatal microvascular, cerebrovascular and cardiovascular diseases, and each component of these vascular diseases.

Self-Reported Frequency of Adding Salt to Food and Risk of Incident Chronic Kidney Disease

Importance

The self-reported frequency of adding salt to foods could reflect a person's long-term salt taste preference, and salt intake has been associated with increased risk of cardiovascular diseases (CVD). Whether self-reported adding of salt to foods is associated with increased risk of chronic kidney disease (CKD) remains unknown.

Objective

To prospectively examine the association of self-reported frequency of adding salt to foods with incident CKD risk in a general population of adults.

Design, Setting, and Participants

This population-based cohort study evaluated UK Biobank participants aged 37 to 73 years who were free of CKD at baseline. Participants were enrolled from 2006 to 2010 and prospectively followed up for disease diagnosis. Data were analyzed from October 2022 to April 2023.

Exposure

Self-reported frequency of adding salt to foods, categorized into never or rarely, sometimes, usually, and always.

Main Outcome and Measure

Incident CKD cases were defined by diagnostic codes. Hazard ratios (HRs) and 95% CIs were calculated by using Cox proportional hazards models. Models were adjusted for several potential confounders including age, sex, race and ethnicity, Townsend Deprivation Index, estimated glomerular filtration rate (eGFR), body mass index, (BMI), smoking status, alcohol drinking status, regular physical activity, high cholesterol, diabetes, CVD, hypertension, infectious disease, immune disease, and nephrotoxic drugs use at baseline.

Results

Within a cohort of 465 288 individuals (mean [SD] age 56.32 [8.08] years; 255 102 female participants [54.83%]; 210 186 male participants [45.17%]), participants with higher self-reported frequency of adding salt to foods were more likely to have a higher BMI, higher Townsend Deprivation Index score, and diminished baseline eGFR compared with those who reported a lower frequency of adding salt to foods. Participants who added salt to their foods were also more likely than those who did not add salt to their foods to be current smokers and have diabetes or CVD at baseline. During a median (IQR) follow-up of 11.8 (1.4) years, 22 031 incident events of CKD were documented. Higher self-reported frequency of adding salt to foods was significantly associated with a higher CKD risk after adjustment for covariates. Compared with those who reported never or rarely adding salt to foods, those who reported sometimes adding salt to food (adjusted HR [aHR], 1.04; 95% CI, 1.00-1.07), those who reported usually adding salt to food (aHR, 1.07; 95% CI, 1.02-1.11), and those who reported always adding salt to food (aHR, 1.11; 95% CI, 1.05-1.18) had an increased risk of CKD (P for trend < .001). In addition, eGFR, BMI, and physical activity significantly modified the associations, which were more pronounced among participants with a higher eGFR, lower BMI, or lower level of physical activity.

Conclusions and Relevance

In this cohort study of 465 288 individuals, a higher self-reported frequency of adding salt to foods was associated with a higher risk of CKD in the general population. These findings suggest that reducing the frequency of adding salt to foods at the table might be a valuable strategy to lower CKD risk in the general population.

Dietary Sodium Intake and Risk of Incident Type 2 Diabetes

OBJECTIVE

To fill the knowledge gap of the relation between long-term dietary sodium intake and type 2 diabetes (T2D), we evaluate the association between the frequency of adding salt to foods, a surrogate marker for evaluating the long-term sodium intake, and incident T2D risk.

METHODS

A total of 402,982 participants from UK Biobank (March 13, 2006 - October 10, 2010) who were free of diabetes, chronic kidney disease, cancer, or cardiovascular disease at baseline, and had completed information on adding salt were analyzed in this study.

RESULTS

During a median of 11.9 years of follow-up, 13,120 incident cases of T2D were documented. Compared with participants who "never/rarely" added salt to foods, the adjusted HRs were 1.11 (95% CI, 1.06 to 1.15), 1.18 (95% CI, 1.12 to 1.24), and 1.28 (95% CI, 1.20 to 1.37) across the groups of "sometimes," "usually," and "always," respectively (P-trend<.001). We did not find significant interactions between the frequency of adding salt to foods and baseline hypertension status and other covariates on the risk of incident T2D. The observed positive association was partly mediated by body mass index, waist to hip ratio, and C-reactive protein, with a significant mediation effect of 33.8%, 39.9%, and 8.6%, respectively. The significant mediation effect of body mass index was largely driven by the body fat mass rather than the body fat-free mass.

CONCLUSION

Our findings for the first time indicate that higher frequency of adding salt to foods, a surrogate marker for a person's long-term salt taste preference and intake, is associated with a higher T2D risk.

Frequency of adding salt at the table and risk of incident cardiovascular disease and all-cause mortality: a prospective cohort study

BACKGROUND

Adding salt at the table is a prevalent eating habit, but its long-term relationship with cardiovascular disease (CVD) and all-cause mortality remains unclear. We evaluated the associations of adding salt at the table with the risk of incident CVD and all-cause mortality.

METHODS

Among 413,109 middle- and old-aged adults without cancer or CVD, all participants reported the frequency of adding salt at the table at baseline. The associations between adding salt at the table and incident CVD (the composite endpoint of coronary heart disease, stroke, heart failure, and CVD deaths) and all-cause mortality were investigated using Cox proportional hazards models.

RESULTS

Of the study population, the mean age was 55.8 years and 45.5% were men; 44.4% reported adding salt at the table; 4.8% reported always adding salt at the table. During a median follow-up of 12 years, there were 37,091 incident CVD cases and 21,293 all-cause deaths. After adjustment for demographic, lifestyle, and cardiometabolic risk factors, the multivariable-adjusted hazard ratios (HRs) for participants who always added salt at the table versus never/rarely added salt at the table were 1.21 (95% confidence interval [CI]: 1.16-1.26) for CVD, 1.19 (95%CI: 1.05-1.35) for CVD mortality, and 1.22 (95%CI: 1.16-1.29) for all-cause mortality, respectively.

CONCLUSIONS

In this prospective cohort study, a higher frequency of adding salt at the table was associated with a greater risk of incident CVD and mortality. Our findings support the benefits of restricting the habit of adding salt at the table in promoting cardiovascular health.

Adding salt to foods and hazard of premature mortality

AIMS

We analyzed whether the frequency of adding salt to foods was associated with the hazard of premature mortality and life expectancy.

METHODS AND RESULTS

A total of 501 379 participants from UK biobank who completed the questionnaire on the frequency of adding salt to foods at baseline. The information on the frequency of adding salt to foods (do not include salt used in cooking) was collected through a touch-screen questionnaire at baseline. We found graded relationships between higher frequency of adding salt to foods and higher concentrations of spot urinary sodium or estimated 24-h sodium excretion. During a median of 9.0 years of follow-up, 18 474 premature deaths were documented. The multivariable hazard ratios [95% confidence interval (CI)] of all-cause premature mortality across the increasing frequency of adding salt to foods were 1.00 (reference), 1.02 (0.99, 1.06), 1.07 (1.02, 1.11), and 1.28 (1.20, 1.35) (P-trend < 0.001). We found that intakes of fruits and vegetables significantly modified the associations between the frequency of adding salt to foods and all-cause premature mortality, which were more pronounced in participants with low intakes than those with high intakes of these foods (P-interaction = 0.02). In addition, compared with the never/rarely group, always adding salt to foods was related to 1.50 (95% CI, 0.72-2.30) and 2.28 (95% CI, 1.66-2.90) years lower life expectancy at the age of 50 years in women and men, respectively.

CONCLUSIONS

Our findings indicate that higher frequency of adding salt to foods is associated with a higher hazard of all-cause premature mortality and lower life expectancy.

Adherence to the Dietary Approaches to Stop Hypertension (DASH) diet and risk of total and cause-specific mortality: results from the Golestan Cohort Study

OBJECTIVE

To evaluate the association between adherence to the Dietary Approaches to Stop Hypertension (DASH) diet and overall and cause-specific mortality in the Golestan Cohort Study (GCS).

METHODS

A total of 50 045 participants aged 40 years or older were recruited from Golestan Province, Iran, from 2004 to 2008 and followed for a mean of 10.64 years. The DASH diet score was calculated for each individual based on food groups. The primary outcome measure was death from any cause.

RESULTS

During 517 326 person-years of follow-up, 6763 deaths were reported. After adjustment for potential confounders, DASH diet score was inversely associated with risk of death from all causes and cancers [hazard ratio (HR): 0.86; 95% confidence interval (CI): 0.75, 0.98; and HR: 0.65; 95% CI: 0.47, 0.90, respectively]. A higher DASH diet score was associated with lower risk of gastrointestinal cancer mortality in men (HR: 0.55; 95% CI: 0.30, 0.99). A greater adherence to DASH diet was also associated with lower other-cancer mortality in women (HR: 0.50; 95% CI: 0.24, 0.99). No association between DASH diet score and cardiovascular disease mortality was observed, except that those dying of cardiovascular disease were younger than 50 years of age and smokers.

CONCLUSIONS

Our findings suggest that maintaining a diet similar to the DASH diet is independently associated with reducing the risk of total death, cancers, and especially gastrointestinal cancers in men.

Healthy Eating Exploratory Program for the Elderly: Low Salt Intake in Congregate Meal Service

OBJECTIVES

This study reported on an exploratory program to help the low income elderly improve healthy eating behavior, specifically by reducing salt intake.

DESIGN

We conducted an exploratory program for 4 weeks for this study. The exploratory program involved offering menus with reduced salt and providing education on healthy eating. After the exploratory program, a survey of the elderly and in-depth interviews allowed us to evaluate the program for foodservice providers (dietitian, social workers, and volunteer workers). This study included both foodservice workers and elderly who actually used the foodservice in a congregate meal service system. This is a unique approach.

SETTING

A congregate meal service center in Seoul, Korea.

PARTICIPANTS

Seventy four elderly in a congregate meal service center.

MEASUREMENTS

Demographics were collected, and the healthy eating program and healthy eating education for elderly respondents were evaluated.

RESULTS

The elderly showed high satisfaction with the exploratory program for healthy eating. We found no significant differences in satisfaction with the program between the elderly who attended education sessions and those who did not, but more of the elderly from the education sessions showed positive behavioral change intentions.

CONCLUSION

The exploratory program influenced to reduce the salt intake of the elderly in congregate meal service. This study suggests cooperation of foodservice providers and the support of administrators is critical to the success of such programs.

Association between the Advanced Glycosylation End Product-Specific Receptor Gene and Cardiovascular Death in Older Men

Advanced glycosylation end product-specific receptor (AGER) signaling has been implicated in atherosclerosis. The aim of this study was to evaluate whether a common genetic variation in the AGER gene is associated with cardiovascular (CV) death. We included 1304 older men who were genotyped for rs1035798:C>T, which is a single nucleotide polymorphism (SNP) mapped to the third intron of AGER. Cox proportional hazard analysis was used to estimate the association of rs1035798:C>T with CV death. In addition we analyzed total RNA extracted from carotid atherosclerosis biopsies of 18 patients that did or did not have recent symptoms of cerebral embolization by quantitative real-time reverse transcription PCR (qRT-PCR). The minor T-allele of rs1035798:C>T was found to be associated with CV death under dominant (HR = 1.43, 95% CI: 1.01–2.02, P = 0.04) and recessive (HR = 2.05, 95% CI: 1.11–3.81, P = 0.02) models of inheritance even after adjustment for traditional cardiovascular risk factors. No association was found between rs1035798:C>T and non-CV death. qRT-PCR results suggested that median relative expression of AGER isoform 1 and isoform 6 transcripts were approximately 6- (P = 0.01) and 2-fold (P = 0.02) greater, respectively, within carotid biopsies of symptomatic compared to asymptomatic patients. These data suggest that the minor (T) allele of rs1035798:C>T represents an independent susceptibility factor for CV death. The expression of AGER isoforms is different in atheroma from patients with recent symptoms. Further studies are needed to investigate if rs1035798:C>T influences the alternative splicing of AGER.