Associations between periodontitis, C-reactive protein, smoking and body mass index

Objectives: The aim of this study was to determine the relationship between circulating C-reactive protein (C-rp), body mass index (BMI), smoking and other risk factors in patients with periodontitis. Methods: 75 newly-referred subjects with adult periodontitis were consented and recruited and gave a full medical, dental and social history in addition to undergoing a clinical periodontal examination and giving a venous blood sample. Serum samples were prepared by centrifugation for 10mins at 11,000 RPM and stored at –700C prior to analysis of C-rp levels using a high sensitivity latex anti-C-rp monoclonal antibody kit with immunonephelometry. Samples were analysed blind to clinical status. The study was approved by the Local Research Ethics Committee. Results: The population included 33 males and 42 females, mean age 44 years (sd 7.5), of whom 30 were smokers, 23 past smokers and 22 never smokers. Mean BMI was 25 (sd 4.5). Subjects had a mean of 29% of sites probing 4-6mm (sd 14%) and 9% (sd 10%) probing 7mm or greater. The median C-rp level was 0.91mg/l (interquartile range 0.42-1.72mg/l). Regression analysis indicated that C-rp levels were significantly related to BMI (p=0.025), percentage of sites probing 4-6mm (p=0.007) and history of previous scaling (p=0.007). When non smokers were excluded, C-rp was significantly related to percentage of sites probing 4mm or greater (P=0.006), amount currently smoked (p=0.029) and current alcohol intake (p=0.032). No associations were seen in never smokers. There were no other significant associations between C-rp and a range of medical, socio-economic, lifestyle and behavioural factors, including dental health behaviour. Conclusions: Within this population, C-rp levels were related to severity of periodontitis, BMI, and other risk factors, but only in the presence of a smoking history.