Patients with higher dietary intake of magnesium had a lower risk of all-cause mortality, said China researchers who surveyed rheumatoid arthritis patients from the NHANES database.
The National Health and Nutrition Examination Survey (NHANES) is conducted yearly by the National Center for Health Statistics, a part of the Centers for Disease Control and Prevention (CDC) in the United States.
“Rheumatoid arthritis patients with higher dietary magnesium intake had an 11.12% reduction of all-cause mortality, [especially] in females aged 65 years and below,” wrote researchers in the Journal of Health, Population and Nutrition.
Rheumatoid arthritis is a chronic inflammatory joint disease with all-cause mortality increasing globally.
Research shows a quarter of the all-cause mortalities in rheumatoid arthritis patients were due to inflammatory markers such as tumour necrosis factor-α, and interleukin-1 and 6, which were significantly increased in rheumatoid arthritis patients.
Researchers therefore hypothesised that inflammation may be a main factor leading to premature death in these patients.
Existing studies reported a 50–60% increase in mortality among rheumatoid arthritis patients compared with healthy people. Active prevention and treatment are thus essential to improving the outcomes of these patients.
Previous research showed that dietary magnesium is an anti-inflammatory nutrient that can reduce all-cause mortality. Furthermore, there are studies that showed higher magnesium intake led to lower risks of inflammatory diseases like hypertension, type 2 diabetes mellitus and cardiovascular disease.
Previous observation studies reported that magnesium intake was inversely related to inflammatory diseases including hypertension, type 2 diabetes mellitus and cardiovascular disease.
Researchers therefore wanted to assess the association between magnesium intake and all-cause mortality in rheumatoid arthritis patients, as this area remains largely unexplored.
The study
For this study, data of rheumatoid arthritis patients were extracted from NHANES 1999–2018. Researchers tracked the patients until 31 December 2019 to assess their survival rate.
In total, 2,181 patients were studied. They were at least 18 years old and had a mean age of 57.52 years.
Data on their dietary intake of magnesium was obtained from a 24-hour dietary recall interview, which was conducted during a physical examination.
Participants had to recall information about their food intake the day before. This includes the time of intake, amount and type food, and detailed food descriptions.
Each reported food item was linked to the USDA’s Food and Nutrient Database for Dietary Studies.
The participants were then split into two groups – one that met the recommended magnesium intake, and one that did not.
The recommended nutrient intake of magnesium for males were 400 mg per day for those aged 18–30 years old, and 420 mg per day for those above 31 years old.
For females, those aged 18–30 years old needed 310 mg per day, and those above 31 years old required 320 mg per day.
Subsequently, researchers conducted subgroup analyses based on different age, gender and body mass index (BMI).
Results
They found that rheumatoid arthritis patients who consumed adequate magnesium from diet as well as supplements may have a lower risk of all-cause mortality.
Out of the 2,181 patients studied, 825, or 37.83%, were all-cause deaths.
The rate of magnesium intake above the recommended nutrition intake was significantly higher in the survival group compared to the all-cause mortality group, i.e. 29.48% versus 18.60%.
Additionally, the overall mortality rate for those who did not meet the recommended magnesium intake was 30.34%. Of those who met the recommended magnesium intake, the figure was 19.22%.
“After taking into account factors like age, race, cardiovascular disease, energy intake, and calcium intake, the results showed that rheumatoid arthritis patients who met the recommended daily intake of magnesium had an 11.12% lower risk of all-cause mortality compared to those who did not,” said the researchers.
They also found that the risk of all-cause mortality in rheumatoid arthritis patients varied significantly with gender and age – there was a stronger association between dietary magnesium intake and reduced mortality observed in females and those under 65.
This can be seen in the hazard ratios for different factors, where a lower value means a lesser risk of all-cause mortality.
For women it was 0.68, while for men it was 0.76; for those aged less than 65 years it was 0.59, for those above 65 it was 0.84.
Results also showed that rheumatoid arthritis patients with a low BMI had a higher risk of all-cause mortality compared to those who were overweight or obese – the hazard ratios for those with a BMI of less than 30 kg/m2 was 0.62, and 0.84 for those with BMI of more than 30 kg/m2.
Keeping a higher dietary magnesium intake may therefore improve the prognosis of RA patients, said researchers.
The researchers recommend consuming more magnesium-enriched foods like dark leafy greens, nuts, legumes, and fibre-rich whole grains.
“Higher dietary magnesium intake may be an efficient measurement to improve the prognosis of rheumatoid arthritis patients, especially in patients with female, aged less than 65 years with a BMI of less than 30 kg/m2.”
Furthermore, because of differences in body composition and structure, women may be more susceptible than men to inflammation. Additionally, hormonal activities in women during phases such as pregnancy and lactation may affect the incidence or course of rheumatoid arthritis.
It is therefore crucial to take gender into account when prescribing treatment.
“Magnesium plays a vital part in regulating endothelial function [cells that control blood flow] and is associated with circulatory markers of systemic inflammation and endothelial dysfunction in women. All these results indicate that gender should be carefully considered in the clinical treatment of rheumatoid arthritis population,” concluded the researchers.
Source: Journal of Health, Population and Nutrition
DOI: 10.1186/s41043-024-00597-1
“Dietary magnesium intake and rheumatoid arthritis patients’ all-cause mortality: evidence from the NHANES database”
Authors: Hantian Liu, Kui Zhang et al.
