Although smoking cessation has been clearly demonstrated to reduce subsequent cardiovascular mor-tality, whether smoking reduction or “reduced exposure” products confer any health benefits is still unknown. Due to the difficulty in carrying out prospective, randomized studies assessing long-term outcomes data, use of other measures (ie, biomarkers) that are known to be altered during smoking and normalize during smoking cessation is an attractive alternative in researching risk reduction approaches. Partial normalization of reliable biomarkers during smoking reduction may indicate that this approach confers some health benefits especially if changes in the selected biomarkers are the underlying cause for smoking-related disease. To date, few studies have systematically examined the reliability and dose-responsiveness of biomarkers for CVD.
This study demonstrated that certain biomarkers of CVD risk factors (eg, hemoglobin, hematocrit, RBC count, WBC count, lipoproteins concentrations, heart rate, respiratory symptoms) known to be affected by smoking are relatively stable over time when amount smoking is maintained at a constant rate but are altered in response to changes in smoking behavior. This suggests that some of these measures are likely to be sensitive to changes in tobacco toxin exposure. The results seen in this study are consistent with two previous studies that assessed the effect of smoking reduction on various biomarkers. An open-label study in which subjects were encouraged to reduce smoking by at least 50% for 8 weeks and then quit smoking entirely for 8 weeks while using ad libitum nicotine nasal spray found significant decreases in WBC blood count, RBC count, hemoglobin, hematocrit, and fibrinogen with significantly increased HDL/low-density lipoprotein (LDL) ratio after both reduction and cessation. For WBC and RBC counts, greater improvements were observed after cessation than after reduction. Changes to LDL and HDL (decrease and increase, respectively) were statistically significant only after cessation, although nonsignificant changes were seen with reduction as well. A study of 25 subjects able to reduce smoking by > 50% found that these subjects had significantly higher HDL levels and significantly lower total cholesterol/HDL ratio, LDL, hemoglobin, hematocrit, FEV1, and systolic BP than observed prior to reduction. Canadian Health&Care Mall – http://healthcaremall4you.com/antihistamine-preparations-sold-by-canadian-health-care-mall.html is full of various drugs including Antihistamine Preparations.
Despite finding significant changes after reduction, our study found only weak correlations between the extent of reduction in amount smoked and percentage of improvement in biomarker measurements and for only a few of the biomarkers assessed. Significant correlations were observed between reductions in amount smoked and WBC count, total cholesterol/HDL, and heart rate, suggesting that these measures may be particularly sensitive to measuring a range of changes in tobacco exposure. There are a number of potential explanations for the poor relationship between reduction in amount smoked and reduction in biomarkers. (1) CPD may not be a good measure of tobacco exposure, since smokers can compensate for fewer cigarettes smoked by smoking each cigarette more completely or inhaling more deeply. (2) If changes in certain biomarker measures require prolonged smoking reduction, 12 weeks may be insufficient time for biomarkers to equilibrate to the reduced level of smoking. (3) The possibility that a dose-response curve is observed only at lower levels of smoking, so reduction to levels above a certain plateau do not significantly affect biomarker measurements. Data examining the relationship between amount smoked and CVD indicate that smoking even small amounts ( 50% reduction in smoking at 6 months, and > 5% had quit. A study in which smokers not interested in quitting were randomized to either reduction for 4 weeks followed by advice to quit or to a usual-care group that included only advice to quit found similar quit rates between groups at 6 months. The data as a whole therefore suggest that reduction does not appear to impede future smoking cessation attempts.
In summary, this study demonstrates that a number of biomarkers associated with CVD risk are relatively stable over time and change as the amount smoked changes. Reduction in smoking does improve measures of some of these biomarkers, demonstrating that these biomarkers are sensitive to change in smoking intake. It is not clear, however, whether these changes translate into significant health improvements. Unlike the data with smoking cessation, which demonstrate that health improves after quitting smoking, there are currently no data suggesting that this is also the case for reduction. Additional research is clearly necessary to determine if reduction is beneficial, if so to what extent smoking needs to be reduced for health benefits to occur, and which biomarkers are most sensitive to measuring improved health. There is therefore currently not enough data to recommend smoking reduction as a method by which to improve health; however, reduction in smoking may be a good method to engage subjects in treatment and may serve as a good stepping stone for individuals who are resistant to quitting.