(My apologies if any of this is totally old hat to you. I guess I'm not totally sure what you mean by helping you read it.)
Blood pressure is expressed as Systolic/Diastolic. These are two different measures/types of pressure on your vascular system and importantly, on your heart. (Systolic is the pressure upon contraction, diastolic is the pressure upon relaxation, if you're curious.)
Normal blood pressure= less than 120/80
High normal blood pressure = between 120/80 and 140/90 (not a concern in itself, but should be monitored in case it goes higher than that)
High blood pressure (hypertension) = 140/90 or above
Very high blood pressure (hypertension) = 180/110 or above
The numbers in the study you mention are for systolic. They indicate
"average plus/minus range". So the smokeless
tobacco users were BP=139.2 ± 17.4, meaning
average was
139.2,
ranging roughly from
121.8 to 156.8
(17.4 was just the largest deviation from the average, whether it was higher or lower, so this range might be narrower.)
(I don't know why they only put a "+" sign, but that's non-standard and I assume they just used "+" as shorthand.)
The average for non-
tobacco users was 4 points lower for systolic.
Next question:
Does the study support its claims?
Well, the study was large (over 400 people) which makes it more robust, and the p-value for all findings is <0.05 which means the findings are statistically significant (i.e. they couldn't have happened by chance -- there's a real difference between the populations).
So this means (if the study methods were sound)
there is a definite increase in blood pressure for smokeless tobacco users. It could be a large impact for some people and zero impact for others, but there is a definite difference.
This isn't really surprising because nicotine is a stimulant, and stimulants...raise your blood pressure!
Is 4 points all that much? Depends. For some people, 4 points (or more - 4 is just the
average!) is enough to put a dangerous amount of extra stress on the heart. For others, it's not a problem. Like caffeine use, some people can take it and some shouldn't. It really depends on other factors in your life (genetics, stress, overall health, etc.).
They studied a village in India, where there's inevitably going to be less obesity, sedentary lifestyles, or other health risk factors. Here in the developed world, we already have incredibly high rates of hypertension. So you just gotta consider your existing risks and baseline BP.
