Risk for high blood pressure, kidney and cardiovascular disease can persist long after E. coli gastroenteritis

Posted on November 28, 2010 by Dr. Jonathan

Research just published in the British Medical Journal presents another example of acute gastrointestinal infection triggering chronic inflammation that persists long after the infection has subsided. The authors set out to…

“…evaluate the risk for hypertension, renal impairment, and cardiovascular disease within eight years of gastroenteritis from drinking water contaminated with Escherichia coli O157:H7 and Campylobacter.”

They followed 1977 adult participants, 1067 of whom came down with acute gastroenteritis when a municipal water system was contaminated. None of them had a history of the subsequent diseases they were looking for which included hypertension (blood pressure ≥140/90 mm Hg), kidney impairment (microalbuminuria or estimated glomerular filtration rate <60 ml/min/1.73 m2), and cardiovascular disease (heart attack, stroke, or congestive heart failure). What did the data show?

“The adjusted hazard ratios for hypertension and cardiovascular disease after acute gastroenteritis were 1.33 and 2.13 respectively. The adjusted hazard ratio for the presence of either indicator of renal impairment was 1.15 and was 3.41 for the presence of both.”

In other words, having a case of acute gastroenteritis resulted in a later increase of 33% in the risk for high blood pressure, 213% for cardiovascular disease, and a whopping 341% for a combination of the two indicators of kidney impairment (microalbuminuria and lower glomerular filtration rate). Thus the authors conclude:

“Acute gastroenteritis from drinking water contaminated with E coli O157:H7 and Campylobacter was associated with an increased risk for hypertension, renal impairment, and self reported cardiovascular disease…Our findings underline the need for following up individual cases of food or water poisoning by E coli O157:H7 to prevent or reduce silent progressive vascular injury…annual blood pressure monitoring and periodic monitoring of renal function may be warranted for individuals who experience acute gastroenteritis after exposure to food or water contaminated with E coli O157:H7.”

This is another example of how GI infections can trigger the long-term immune system dysregulation that promotes chronic inflammation, the biological basis of cardiovascular disease and renal impairment. Clinicians should be diligent in diagnosing GI infection and astute in examining for immune dysfunction and occult autoimmune disorders.

Don’t over-medicate high blood pressure

Posted on July 21, 2010 by Dr. Jonathan

There are still many practitioners treating patients for hypertension who believe that systolic blood pressure should be suppressed to less than 130 mm Hg with medication. Another study just published in JAMA (The Journal of the American Medical Association) adds more evidence that this is not helpful even for individuals with diabetes and coronary artery disease. The authors set out to:

“…determine the association of systolic BP control achieved and adverse cardiovascular outcomes in a cohort of patients with diabetes and CAD (coronary artery disease).”

They analyzed data for 6400 subjects from 862 sites in 14 countries for more than ten years.

“Patients received first-line treatment of either a calcium antagonist or β-blocker followed by angiotensin-converting enzyme inhibitor, a diuretic, or both to achieve systolic BP of less than 130 and diastolic BP of less than 85 mm Hg. Patients were categorized as having tight control if they could maintain their systolic BP at less than 130 mm Hg; usual control if it ranged from 130 mm Hg to less than 140 mm Hg; and uncontrolled if it was 140 mm Hg or higher.”

The data they accumulated painted this picture:

“…little difference existed between those with usual control and those with tight control…The all-cause mortality rate was 11.0% in the tight-control group vs 10.2% in the usual-control group; however, when extended follow-up was included, risk of all-cause mortality was 22.8% in the tight control vs 21.8% in the usual control group.”

Note that the tight control group had a slightly higher risk of all-cause mortality over the longer time period. Besides the greater likelihood of adverse effects with higher doses of medication, lower blood pressure means diminished delivery of oxygen to tissues (the pressure acts to overcome the increased resistance of less a healthy circulatory system).

Their conclusion clearly states the lack of benefit with suppression to less than 130 mm Hg:

“Tight control of systolic BP among patients with diabetes and CAD was not associated with improved cardiovascular outcomes compared with usual control.”

See another recent study that proves the same point.

Both are good for weight loss, which is better for high blood pressure: higher protein or higher fat?

Posted on April 17, 2010 by Dr. Jonathan

European Journal of Clinical Nutrition 0310 Most of you reading this are aware that a lower glycemic diet can promote weight and fat loss through its beneficial effect on insulin levels. But which is better for blood pressure control, a higher or lower protein to fat ratio? This study recently published in the European Journal of Clinical Nutrition was designed to answer that question.

“There is controversy over dietary protein’s effects on cardiovascular disease risk factors in diabetic subjects. It is unclear whether observed effects are due to increased protein or reduced carbohydrate content of the consumed diets. The aim of this study was to compare the effects of two diets differing in protein to fat ratios on cardiovascular disease risk factors.”

What did their data show? Interestingly,…

“Both diets were equally effective in promoting weight loss and fat loss and in improving fasting glycemic control, total cholesterol and low-density lipoprotein (LDL) cholesterol, but the…HP–LF [high protein-low fat] diet improved significantly both systolic and diastolic blood pressure when compared with the LP–HF [low protein-high fat] diet. No differences were observed in postprandial glucose and insulin responses.”

The authors conclude:

“A protein to fat ratio of 1.5 in diets significantly improves blood pressure and TG [triglyceride] concentrations in obese individuals with DM2 [type 2 diabetes].”