Plant-Based Diets and All-cause and Cardiovascular Mortality in a Nationwide Cohort in Spain: The ENRICA Study

A plant-based diet index to study the relation between diet and disease risk among adults: a narrative review

Plant-based diets (PBD) may offer various health benefits and contribute to a sustainable way of life, but, if not planned correctly, may also confer risks, e.g., by focusing on plant foods with low nutrient density, such as foods primarily consisting of refined carbohydrates. A plant-based diet index (PDI) differentiating between a healthful, unhealthful, and overall PBD, offers a promising approach to standardize and compare studies and integrate results. In this review we (1) summarize current evidence on the PDI and disease risk of relevance to public health, (2) discuss the methodology of the PDI and how it can be sensibly applied in further studies and (3) indicate areas with a lack of knowledge, such as vulnerable populations. In summary, our amalgamation shows, that adherence to a healthier plant-based diet is associated with an 8-68% lower risk for metabolic risk factors, diabetes, and cardiovascular disease, while adherence to an unhealthier plant-based diet is associated with a 10-63% higher risk. Although differences in calculation methods and underlying diet patterns between populations should be accounted for, the PDI can be a useful tool to assess adherence to different plant-based diet patterns and their association with health outcomes in cohort studies across cultures.

Plant-based dietary patterns and mortality from all causes, cardiovascular disease, and cancer: The Multiethnic Cohort Study

BACKGROUND & AIMS

Plant-based dietary patterns have been associated with lower risk of cardiovascular disease (CVD), some cancers, and related mortality in U.S.

POPULATIONS

However, the quality of plant foods has rarely been considered in the association between plant-based diets and mortality, especially in a population with various racial and ethnic backgrounds. We investigated whether the adherence to plant-based dietary patterns and the healthiness of plant foods are associated with mortality from all causes, CVD, and cancer and evaluated how the association varies by race and ethnicity.

METHODS

A total of 144,729 African American, Japanese American, Latino, Native Hawaiian, and White men and women who participated in the Multiethnic Cohort Study (1993-2019) were included. Cox models were used to estimate HR and 95% CI of mortality from all causes, CVD, and cancer across quintiles of three plant-based diet scores: overall plant-based diet index (PDI), healthful plant-based diet index (hPDI), and unhealthful plant-based diet index (uPDI).

RESULTS

Over an average 21 years of follow-up, we identified 65,087 deaths, including 18,663 from CVD and 16,171 from cancer. Comparing the highest versus lowest quintiles, greater scores of PDI and hPDI were associated with a lower risk of all-cause mortality in both men (HR = 0.85, 95% CI: 0.82-0.89 for PDI; HR = 0.88, 95% CI: 0.85-0.91 for hPDI; both P for trend <0.0001) and women (HR = 0.89, 95% CI: 0.86-0.93 for PDI; HR = 0.86, 95% CI: 0.83-0.89 for hPDI; both P for trend <0.0001). An increased risk of all-cause mortality with uPDI was observed only in women (HR = 1.11, 95% CI: 1.07-1.15, P for trend <0.0001; P for heterogeneity by sex = 0.019). A similar trend was shown for CVD mortality with a significant increase in risk with uPDI for both men and women. PDI was associated with a lower risk of cancer mortality in men (HR = 0.86, 95% CI: 0.80-0.92, P for trend <0.0001), while neither hPDI nor uPDI was associated in either sex. Compared with the other racial and ethnic groups within each sex, the association of uPDI with all-cause mortality was stronger in White men (P for heterogeneity by race and ethnicity = 0.009) and weaker in Latino women (P for heterogeneity = 0.002).

CONCLUSION

A healthy plant-based dietary pattern emphasizing the quality of plant foods was associated with a lower risk of all-cause and CVD mortality in both men and women, although the magnitude of the associations varied across racial and ethnic groups.

Plant-Based Diets and Risk of Multimorbidity: The Health and Retirement Study

BACKGROUND

Plant-based diets have gained attention due to their beneficial effects against major chronic diseases, although their association with multimorbidity is mostly unknown.

OBJECTIVES

We examined the association between the healthful (hPDI) and unhealthful plant-based diet indices (uPDI) with multimorbidity among middle-aged and older adults from the United States.

METHODS

Data on 4262 adults aged >50 y was obtained from the 2012-2020 Health and Retirement Study (HRS) and 2013 Health Care and Nutrition Study (HCNS). Food consumption was collected at baseline with a food frequency questionnaire and 2 PDIs were derived: the hPDI, with positive scores for healthy plant foods and reverse scores for less healthy plant foods and animal foods; and the uPDI, with only positive scoring for less healthy plant foods. Complex multimorbidity, defined as ≥3 coexistent conditions, was ascertained from 8 self-reported conditions: hypertension, diabetes, cancer, chronic lung disease, heart disease, stroke, arthritis, and depression. Cox proportional hazards models were used to estimate the hazard ratios (HRs) and 95% confidence intervals (CIs).

RESULTS

After a median follow-up of 7.8 y, we documented 1202 incident cases of multimorbidity. Compared with the lowest quartile, higher adherence to the hPDI was inversely associated with multimorbidity (HR for quartile 3: 0.77; 95% CI: 0.62, 0.96 and HR for quartile 4: 0.79; 95% CI, 0.63, 0.98; P-trend = 0.02). In addition, a 10-point increment in the hPDI was associated with a 11% lower incidence of multimorbidity (95% CI: 1, 20%). No significant associations were found for the uPDI after adjusting for sociodemographic and lifestyle factors.

CONCLUSIONS

Higher adherence to the hPDI was inversely associated with multimorbidity among middle-aged and older adults. Plant-based diets that emphasize consumption of high-quality plant foods may help prevent the development of complex multimorbidity.

Pro-vegetarian dietary patterns and mortality by all-cause and specific causes in an older Mediterranean population

PURPOSE

Pro-vegetarian (PVG) dietary patterns have shown health benefits, although the evidence concerning their association with mortality is scarce, particularly in older populations. We investigated the effect of three defined PVG patterns on all-cause, cardiovascular disease (CVD) and cancer mortality risk in an older Mediterranean population.

METHODS

We analysed baseline data from 597 adults aged 65 and older who participated in a population-based cross-sectional study, and mortality during a 12-year period. We used a validated food frequency questionnaire to estimate the adherence in tertiles to three evidence-based PVG dietary patterns: a general PVG pattern (gPVG) and two specific variations (healthful -hPVG, and unhealthful -uPVG). The gPVG pattern incorporated data from 12 food groups, consisting of 7 plant-based and 5 animal-based. The hPVG and uPVG versions included information from 18 food groups (4 food groups added and the splitting of 2 food groups). We used Cox regression to estimate hazard ratios (HR) and 95% confidence intervals (CI) adjusting for relevant covariates.

RESULTS

After the 12-years follow-up period, moderate adherence to hPVG pattern was associated with lower all-cause and CVD mortality whereas greater adherence to uPVG pattern was associated with higher all-cause and CVD mortality. Compared with those in the lowest tertile, participants in the second tertile of adherence to the hPVG pattern showed a significant lower risk of all-cause mortality (HR = 0.59; 95%CI: 0.43, 0.82) and CVD mortality (HR = 0.47; 0.28, 0.78). Participants in the highest tertile of adherence to the uPVG showed an increased mortality risk of all-cause (HR = 1.53; 1.07, 2.19) and CVD (HR = 2.10; 1.19, 3.70). No significant associations were found between adherence to any of the PVG dietary patterns and cancer mortality.

CONCLUSION

Moderate adherence to a healthy PVG pattern reduced the long-term mortality risk for all-cause and CVD in an older Mediterranean population, while higher adherence to an unhealthy PVG pattern increased the risk of all-cause and CVD mortality.

Association between Plant-based Diet and Risk of Chronic Diseases and All-Cause Mortality in Centenarians in China: A Cohort Study

Background

Numerous studies have suggested the health benefits of a plant-based dietary pattern. However, whether this dietary pattern is associated with health benefits for centenarians remains unexplored. Our study aimed to investigate the correlation between 16 widely consumed Chinese food items and the incidence rates of chronic diseases and all-cause mortality among centenarians.

Methods

We conducted a dietary survey on 3372 centenarians with an average age of 102.33 y in China. After rigorous screening, we identified 2675 centenarians, who underwent a 10-y follow-up study with all-cause mortality as the primary outcome. We developed 6 dietary patterns on the basis of the food consumption frequency of each participant. To model the impact of missing values, we employed multiple imputation methods, verifying the robustness of models.

Results

The overall plant-based diet index (PDI), healthy plant-based diet index (hPDI), unhealthy plant-based diet index (uPDI), healthy plant-based foods index (HPF), unhealthy plant-based foods index (uHPF), and animal-based foods index (AF) scores among centenarians in China were 46.95 ± 6.29, 44.43 ± 5.76, 51.09 ± 6.26, 21.63 ± 4.79, 9.91 ± 2.41, and 14.59 ± 3.58, respectively. High scores of PDI, hPDI, and HPF were associated with a lower risk of chronic diseases. In the 10-y follow-up study, 92.90% of centenarians have died. The high scores of the PDI (HRPDI = 0.81), hPDI (HRhPDI = 0.79), and HPF (HRHPF = 0.81) scores were significantly associated with a lower risk of death compared with the low scores. Conversely, the high AF score (HRAF = 1.17) was significantly associated with a higher risk of death compared with the low scores.

Conclusion

Despite the fact that a higher score in both a predominantly plant-based dietary pattern and a healthy dietary pattern can decrease the death among centenarians, not all HPFs have this effect. A higher AF predicted a higher risk of mortality, whereas higher PDI, hPDI, and HPF were associated with a lower risk of mortality among Chinese centenarians.

Scoping review of the association of plant-based diet quality with health outcomes

Introduction

The association of plant-based dietary patterns with health outcomes has traditionally been assessed without considering nutritional value. The plant-based dietary index (PDI), first published in 2016, overcomes this limitation with both a healthful PDI (hPDI) and an unhealthful PDI (uPDI), based on the quality of plant foods consumed plus the frequency of animal foods. We sought to summarize the breadth of research using the hPDI and uPDI to gain insight into how the quality of plant-based dietary patterns might be associated with health outcomes.

Methods

Scoping review of studies that used the PDI, hPDI, or uPDI to report associations with health outcomes. Multiple databases were searched from 2010 through April 2023 with 2 authors independently assessing eligibility and extracting data. In addition to assessing the association of the indices to health outcomes, we determined the frequency of concordant or discordant findings for hPDI versus PDI and for hPDI versus uPDI.

Results

We included 95 articles (54% longitudinal, 37% cross-sectional, and 9% case-control) with a median sample size of 3,646. Higher hPDI levels were associated with favorable health outcomes in 36% of comparisons (most often for obesity, mortality, diabetes, cardiovascular disease, and psychiatric disorders), compared to 25% for the PDI and only 2% for the uPDI. Conversely, higher levels of the uPDI were associated with unfavorable health outcomes in 33% of comparisons, in contrast to under 1% for the hPDI and 2% for the PDI. When the hPDI association to an outcome was discordant with the uPDI or PDI, the significance and directionality always favored the hPDI over the uPDI, and nearly always favored the hPDI over the PDI.

Discussion

Dietary indices that account for the quality of plant foods can show health benefits that might be missed by a generic plant-based index. A greater focus on the quality of plant foods could improve nutrition guidelines, raise awareness about the benefits of adding unrefined plant foods to the diet, and empower consumers to make incremental additions of such foods to displace unhealthy foods. We anticipate increasing use of indices that address food quality in future research.