Rates of consumption since 1965 in the developed world have either peaked or declined. However, they continue to climb in the developing world. As of 2008 to 2010, tobacco is used by about 49% of men and 11% of women aged 15 or older in fourteen low-income and middle-income countries (Bangladesh, Brazil, China, Egypt, India, Mexico, Philippines, Russia, Thailand, Turkey, Ukraine, Uruguay and Vietnam), with about 80% of this usage in the form of smoking. The gender gap tends to be less pronounced in lower age groups.Many smokers begin during adolescence or early adulthood. During the early stages, a combination of perceived pleasure acting as positive reinforcement and desire to respond to social peer pressure may offset the unpleasant symptoms of initial use, which typically include nausea and coughing. After an individual has smoked for some years, the avoidance of withdrawal symptoms and negative reinforcement become the key motivations to continue. A 2009 study of first smoking experiences of seventh-grade students found out that the most common factor leading students to smoke is cigarette advertisements. Smoking by parents, siblings and friends also encourages students to smoke. History
Use in ancient cultures
Smokings history dates back to as early as 5000–3000 BC, when the agricultural product began to be cultivated in Mesoamerica and South America; consumption later evolved into burning the plant substance either by accident or with intent of exploring other means of consumption. The practice worked its way into shamanistic rituals.
In June 2010, they published a retrospective study comparing roziglitazone to pioglitazone, the other thiazolidinedione marketed in the United States and concluded rosiglitazone was associated with "an increased risk of stroke, heart failure, and all-cause mortality and an increased risk of the composite of AMI, stroke, heart failure, or all-cause mortality in patients 65 years or older". The number needed to harm with roziglitazone was sixty. Graham argued rosiglitazone caused 500 more heart attacks and 300 more heart failures than its main competitor. Two meta analyses released in 2010, one incorporating 56 trials and a second incorporating 164 trials reached conflicting conclusions. Nissen et al. found again an increased risk for heart infarction against control, but no increased risk for cardiovascular death. Mannucci et al. found no statistically significant increase in cardiac events but a significant increase in heart failure. A 2011 drug class review found an increased risk of cardiovascular adverse events.A meta-analysis of 16 observational studies released in March, 2011, compared rosiglitazone to pioglitazone, finding support for greater cardiovascular safety for pioglitazone. The meta-analysis involved 810 000 patients taking rosiglitazone or pioglitazone. The study suggests 170 excess myocardial infarctions, 649 excess cases of heart failure, and 431 excess deaths for every 100 000 patients who receive rosiglitazone rather than pioglitazone.