Periodontitis and general health: what the studies really show

Four questions not to confuse

For each disease, four questions arise, and none of them answers the next. Association: do people with periodontitis have this disease more often? Observational studies tell us. Mechanisms: are there plausible biological pathways? Laboratory, animal and human studies. Direct or indirect link: does the link run through bacteria and inflammation from the gums, or through factors the two diseases share, such as smoking, age, diabetes or social circumstances? Treatment effect: does treating periodontitis improve the general disease? Randomised trials, in which treatment is allocated by chance, answer it.

The table below sums up, condition by condition, what the studies show and the mechanisms studied.

The relationships studied, in one table

Which mechanisms connect the mouth to the rest of the body?

• Bacteraemia: through the ulcerated lining of periodontal pockets, bacteria briefly enter the bloodstream, even during chewing or brushing ^[6].
• Low-grade inflammation: inflammatory mediators (IL-6, TNF-α) and CRP, a protein made by the liver, rise in the blood; periodontal treatment brings CRP down by 0.69 mg/L on average at six months ^[7].
• Oral–gut spread: swallowed bacteria and immune cells activated in the mouth can reach the gut, according to animal models ^[6].
• Endothelial dysfunction: the inner lining of the arteries dilates less well; it recovers six months after intensive periodontal treatment ^[8].
• Trained myelopoiesis: periodontal inflammation durably 'programmes' bone-marrow stem cells, which then release more reactive white blood cells; described mainly in animals, this mechanism could link several inflammatory diseases ^[6].

Pregnancy, kidneys, rheumatoid arthritis: three links to know

Pregnancy. Under the influence of hormones, the gums react more to plaque, and gum bleeding is common in pregnant women ^[10]. Observational studies find an independent association between periodontitis and preterm birth, low birth weight or pre-eclampsia ^[10]. As for treatment, the Cochrane review finds a possible reduction in low birth weight ^[11]. In these trials, non-surgical periodontal treatment was carried out during pregnancy; a current or planned pregnancy should therefore be mentioned to the practice.

Chronic kidney disease. In a large population study, severe periodontitis goes hand in hand with lower kidney function and more albumin in the urine ^[12]. CRP falls after periodontal treatment ^[13]. Anyone under follow-up for kidney disease has every reason to mention it and their medication, and the periodontal report can be sent to the nephrologist.

Rheumatoid arthritis. A meta-analysis finds more periodontitis in patients with rheumatoid arthritis than in healthy controls ^[14]. The mechanism studied involves P. gingivalis, which can modify proteins (citrullination) that patients' immune systems then turn against ^[6]. After non-surgical periodontal treatment, disease activity (DAS28 score) falls in the short term in the available trials, with follow-up of six weeks to six months ^[15]. When the hands are affected, brushing becomes difficult: aids can be discussed at the consultation.

The best-documented links

The best-documented link concerns diabetes: the 2022 Cochrane review measures a fall in HbA1c after periodontal treatment, with moderate certainty ^[3]. For the heart and blood vessels, the association is firmly established and some markers improve after treatment ^{[5] [7] [8]}. For Alzheimer's disease, meta-analyses find a risk about 20% higher, and P. gingivalis has been found in patients' brains ^{[16] [17] [18]}. For digestive cancers, periodontitis is associated with a higher risk of colorectal, oesophageal, gastric and pancreatic cancer ^{[23] [28] [29]}. Each article details the studies.

Periodontitis is treated first in its own right: it destroys bone and costs teeth. Two measures have an established benefit for both the gums and general health: stopping smoking and controlling diabetes ^[27].

Prevention, nutrition, micronutrition: what place for this perspective?

Dr Hazout has extended his training as a periodontist with a university diploma (DU) in anti-ageing and preventive medicine (2025) and a European university diploma in micronutrition and preventive medicine (2026). This perspective helps to read the inflammatory background on which periodontitis takes hold; it accompanies the mechanical treatment of the pockets and never stands in for it. The consultation therefore includes a lifestyle review: smoking, diet (free sugars, ultra-processed foods), physical activity, sleep, current medication and medical history.

• If you have risk factors for diabetes and no recent check-up, Dr Hazout suggests raising it with your GP, as the scientific societies recommend ^[27]; with your consent, the practice sends them a periodontal report.
• Diet weighs on gum inflammation: the trials, their limits and the advice that follows are detailed in the article on nutrition, micronutrition and inflammation.
• No food supplement is offered as a matter of course, and none treats periodontitis; tests and supplements are sorted out in the article on blood tests and supplements.

What this means for you

If you live with a general disease and have signs of periodontitis (bleeding gums, receding gums, loose teeth), the two sets of care benefit from knowing about each other. At the practice in Levallois-Perret, your medical situation is taken into account from the first visit. Periodontitis treatment is the same as for any patient, adjusted to your state of health, and maintenance preserves the results.

If you are in good health, remember this: periodontitis is common, often silent, and it is treated first because it damages the mouth. A benefit for the heart or the brain is possible.

Frequently asked questions