A cross-sectional study of relationships between periodontal disease and general health: The Hitachi Oral Healthcare Survey

BACKGROUND

This cross-sectional study performed to clarify the relationship between periodontal disease and non-communicable diseases (NCDs), such as obesity, diabetes mellitus, impaired glucose tolerance (IGT), chronic obstructive pulmonary disease (COPD), and atherosclerotic cardiovascular disease (ASCVD) by introducing dental examinations into the annual health examinations conducted by Japanese companies, and to highlights the importance of a medical system that connects dental and medical professionals.

METHODS

A total of 1.022 Hitachi Ltd. employees were enrolled in this cross-sectional study. We examined correlations and odds ratios (ORs) between the dental and overall health of employees using stratification and multiple logistic regression analyses based on the periodontal health indicators, general health indicators, and occlusal force.

RESULTS

The adjusted OR of PPD for obesity (OR, 1.42; 95% confidence interval [CI], 1.09-1.84; p = 0.009), IGT (OR, 1.48; 95% CI, 1.00-2.20; p = 0.049), and COPD (OR, 1.38; 95% CI, 1.02-1.88; p = 0.038) significantly differed. The adjusted OR of body mass index (OR, 1.28; 95% CI 1.15-1.42; p < 0.001), haemoglobin A1C (HbA1c) (OR, 4.34; 95% CI, 1.89-9.98; p < 0.001), fasting blood glucose (FBG) levels (OR, 1.08; 95% CI 1.04-1.11; p < 0.001), postbronchodilator forced expiratory volume in one second/forced vital capacity ratio (%FEV1) (OR, 0.95; 95% CI 0.91-1.00; p = 0.031) and smoking (OR, 2.32; 95% CI 1.62-3.33; p < 0.001) for severe periodontal disease also significantly differed. Occlusal force was significantly reduced in employees aged 50-59 years compared to those aged 40-49 years. Both PPD, HbA1c, FBG levels were significantly associated with occlusal force among employees with moderate/severe periodontitis. PPD was significantly associated with occlusal force among employees with and moderate COPD, and ASCVD. %FEV1 was significantly associated with occlusal force among employees with IGT.

CONCLUSIONS

This cross-sectional study revealed mutual relationships among periodontal disease, NCDs, and occlusal force on Japanese corporate workers. We demonstrated that a comprehensive, regional healthcare system centred on annual integrated dental and physical health examinations in the workplace will benefit employees and positively impact corporate health insurance.

Effects of treatment with nilvadipine on cerebral ischemia in rats

The protective effects of a Ca2+ antagonist, nilvadipine, on focal cerebral ischemia were studied in male spontaneously hypertensive rats. The animals received either nilvadipine (3mg x kg(-1) x day(-1)) or a vehicle subcutaneously. Group 1 (n=11) was treated for 7 days, and Group 2 (n=11) for 14 days. The middle cerebral artery was occluded on the 6th (Group 1) or 13th (Group 2) day of the treatment, and neuropathological outcomes were quantified 24 hours later. The mean arterial blood pressure was significantly reduced with nilvadipine to normal levels. The % infarct volumes of Groups 1 (37+/-2) and 2 (34+/-3) were significantly less than those of their controls (39+/-3 [n=11] and 40+/-4 [n=12], respectively), although the difference between Groups 1 and 2 was not significant. When infarct areas were compared in each of 8 coronal sections, the infarct size had decreased in the 5 posterior sections in Group 2, but only in 2 sections of Group 1. A significant decrease in the edema volumes was observed in Group 2, but not in Group 1. Thus, nilvadipine provided protective effects against cerebral ischemia in rats having chronic hypertension, and the effects were dependent on the duration of treatment.

Protective effect of nilvadipine on focal cerebral ischemia in spontaneously hypertensive rats

The protective effect of nilvadipine, a Ca2+ antagonist, on cerebral ischemia was investigated in spontaneously hypertensive rats. The 12-week-old animals were treated for 7 days with either nilvadipine or vehicle using osmotic pumps implanted subcutaneously. Group 1 animals (n = 10) received the vehicle, and Group 2 (n = 10) and 3 animals (n = 10) received 1 and 3 mg/kg/day nilvadipine, respectively. The left middle cerebral artery was occluded under halothane anesthesia on the 6th day of treatment, and neuropathological outcomes were quantified 24 hours later. The systolic blood pressure measured before occlusion decreased to 137 +/- 9 mmHg (Group 2) and 130 +/- 9 mmHg (Group 3), compared to 189 +/- 12 mmHg for Group 1 (p < 0.05). The percentage infarct volumes in Groups 1-3 were 39 +/- 3%, 37 +/- 2%, and 34 +/- 3%, respectively (p < 0.05, Groups 1 vs. 3). Therefore, nilvadipine decreased the infarct size dose-dependently. Nilvadipine has a protective effect against cerebral ischemia in rats with chronic hypertension. Neuropathological findings suggest that nilvadipine may act at the ischemic penumbra. Nilvadipine may have the additional benefit of reducing the consequences of a possible later stroke in patients with hypertension (one of the risk factors for stroke).

Failure of normobaric oxygen therapy to reduce ischemic brain damage in rats

We investigated the effects of 24-h oxygen therapy on focal cerebral ischemia in rats. Under halothane anesthesia, a 3-0 nylon thread was introduced into the neck internal carotid artery to occlude the left middle cerebral artery (MCA). Under atmospheric pressure, group 1 animals inhaled standard air; group 2, 40% O2; group 3, 60% O2; and group 4, 100% O2. Neuropathologic outcomes were quantified after a 24-h inhalation period. Infarct volumes tended to decrease in groups 2-4, but the decreases were not significant when compared with group 1. Hemispheric volume differences of groups 2-4 (27 +/- 18 mm3, 22 +/- 17 mm3, and 31 +/- 22 mm3, respectively) were less than that of group 1 (61 +/- 23 mm3, P < 0.05). Our results demonstrate that O2 therapy reduces brain swelling in rats 24 h after MCA occlusion. However, a dose-dependent decrease in brain swelling was not observed. In addition, we failed to see a significant decrease in the infarct size.

Reversible middle cerebral artery occlusion in rats using an intraluminal thread technique

We investigated the temporal profile for neuropathologic outcomes after cerebral ischemia using a rat model of reversible middle cerebral artery occlusion, where reperfusion can be introduced in nonanesthetized rats. Reperfusion was performed 1 hour to 5 hours after the occlusion. Control animals underwent permanent occlusion. The results indicate that the time window to reduce infarct volume is 2 hours, and that a > or = 3-hour duration of ischemia is sufficient to attain the maximal infarction observed after permanent ischemia. This suggests that any therapies that follow the therapeutic window will provide little benefit for transient cerebral ischemia and reperfusion injury.

Therapeutic effects of nilvadipine on rat focal cerebral ischemia

The present study was conducted to investigate the therapeutic effects of nilvadipine, a Ca2+ entry blocker, on rat focal cerebral ischemia. Under halothane anesthesia, a 3-0 nylon thread was introduced into the neck internal carotid artery to occlude the left middle cerebral artery. Either nilvadipine (3.2 mg/kg) or vehicle was administered subcutaneously 1, 2, 3, 4, 5 and 6 h following the occlusion (groups 1-6, respectively). Twenty-four hours after the occlusion, the percentage infarct volumes in nilvadipine-treated animals in groups 1-3 (21 +/- 11%, 24 +/- 11%, and 26 +/- 7%, respectively) were smaller than those in the respective control groups (36 +/- 5%, 35 +/- 3%, and 35 +/- 3%; P < 0.05). Compared with controls, the infarct size of the periphery of the fronto-parietal cortex decreased in nilvadipine-treated animals. The results indicate that nilvadipine decreases the size of infarction when administered up to 3 h after an ischemic insult. Thus, nilvadipine can be considered a potential therapeutic agent for acute focal cerebral ischemia, and may be clinically useful in stroke patients.

AT-877, a Ca2+ antagonist, fails to reduce infarct size following rat middle-cerebral artery occlusion

We investigated the effects of AT-877, a Ca2+ antagonist, on rat middle-cerebral artery occlusion. All rats had 6-h ischemia, and treated animals received either 3 or 10 mg/kg AT-877 s.c. just after the occlusion. Control animals received an equal volume of the vehicle. Prior to sacrifice, significant changes in the decrease of blood pressure and the increase of plasma glucose were observed in the treated rats. Although the infarct size tended to decrease, this decrease was not significant. Only when the blood pressure- or plasma glucose-matched subgroups were compared, the infarct volume decreased significantly in the drug-treated animals. Thus, AT-877 failed to reduce ischemic brain damage unless the blood pressure or plasma glucose were controlled.

Rat middle cerebral artery occlusion using an intraluminal thread technique

A modification of the previous methods of producing cerebral ischaemia in rats (Koizumi et al., Longa et al.), using an intraluminal thread technique, is described. The middle cerebral artery is occluded by introducing a simple 3-0 nylon thread (0.20-0.249 mm in diameter) through the internal carotid artery in the neck. It has been proven that with this method reproducible focal cerebral ischaemia can be achieved which resembles human stroke. Therefore this simple and relatively non-invasive model is suitable for the pathophysiological investigation of ischaemic stroke and the testing of potential therapies.

Attenuated neuropathology by nilvadipine after middle cerebral artery occlusion in rats

We investigated the effects of nilvadipine, a calcium antagonist, on cerebral ischemia in rats. Under halothane anesthesia, 30 rats had a 3-0 nylon suture introduced through the extracranial internal carotid artery to occlude the left middle cerebral artery. Nilvadipine was dissolved in polyethylene glycol 400. Immediately following occlusion, group 1 rats (n = 10) were treated subcutaneously with vehicle and group 2 and 3 rats were treated with 1.0 (n = 10) and 3.2 (n = 10) mg/kg nilvadipine, respectively. Perfusion fixation was performed 24 hours later, and the histopathologic outcomes were quantified. In group 1 infarct volume was 28.2 +/- 11.4% of the total cerebral volume; in groups 2 and 3 infarct volumes were 25.5 +/- 11.6% (NS) and 13.9 +/- 9.2% (p less than 0.05 different from group 1), respectively. Nilvadipine decreased ischemic neuronal injury in a dose-dependent manner and may be of use in the treatment of cerebral ischemia.

Effects of a Ca2+ entry blocker (nilvadipine) on acute focal cerebral ischemia in rats

The effects of nilvadipine, a Ca2+ entry blocker, on focal cerebral ischemia were investigated in rats having unilateral middle cerebral artery occlusion. All rats had 24 h ischemia, and were divided into three groups (ten rats per group). Groups 1 and 2 received 1.0 and 3.2 mg/kg nilvadipine s.c. respectively, just after the occlusion. Control rats received an equal volume of the vehicle. Control animals had a % infarct volume of 28.2 +/- 11.4%, and a left/right hemispheric volume ratio of 112 +/- 12%. Group-1 and -2 rats had % infarct volumes of 25.5 +/- 11.6% and 13.9 +/- 9.2% (p less than 0.01) respectively, and left/right hemispheric volume ratios of 111 +/- 9% and 103 +/- 7% (p less than 0.05), respectively. Thus, the drug reduced the infarct size and the brain edema in a dose-dependent manner. The significant decrease in the infarct volume was observed in the periphery of the frontoparietal cortex. This study supports the hypothesis that nilvadipine may be a potential therapeutic agent for cerebral ischemia. Neuropathological findings suggest the possible therapeutic effects of the drug in the ischemic penumbra.

Therapeutic effects of hyperbaric oxygenation on acute focal cerebral ischemia in rats

The effects of hyperbaric oxygenation on acute focal cerebral ischemia in rats were investigated. All rats suffered 4-hour middle cerebral artery occlusion. Nontreated controls had a 27.9% +/- 5.5% infarct volume, and a left/right hemispheric volume ratio of 109% +/- 3%. Animals treated between 2.5 and 3.5 hours following occlusion had an 18.1% +/- 9.7% infarct volume (p less than 0.01), and a 105% +/- 3% left/right hemispheric volume ratio (p less than 0.001). In conclusion, at least until 4 hours following an ischemic insult, hyperbaric oxygenation reduces ischemic neuronal injury and brain edema following middle cerebral artery occlusion in rats treated between 2.5 and 3.5 hours following occlusion.