People who live in areas with ‘bad air’ and smokers have an increased risk of developing chronic obstructive pulmonary disease (COPD). COPD affects over 600 million people worldwide and this represents about 10% of adults 40 years or older. In many Western countries, COPD is the leading cause of medical hospitalization. In 1990, COPD was the sixth most common cause of death worldwide. However, it is predicted that COPD will become the third most common cause by 2020.

As COPD patients have an underlying lung disease / injury, one would expect lung related conditions to be the main cause of morbidity and mortality. In the community, > 80% of COPD cases are mild to moderate COPDs [Global Initiative for Chronic Obstructive Lung Disease (GOLD) stages 1 and 2]. For these individuals, the leading cause of morbidity is actually cardiovascular disease (CVD) and not lung related problems. The leading cause of mortality COPDs is lung cancer (Curr Opin Pulm Med 2008; 14: 115 – 121).

Why is CVD more common if you have COPD? While the exact reasons are not known, two mechanisms have been postulated. An underlying neuro-humoral disturbance leads to excess sympathetic nervous activity. This raises the resting heart rate and increases the risk of arrhythmias (abnormal heart rate) as seen in COPD patients. Apart from lung inflammation, COPD patients also have evidence of systemic inflammation. Using C-reactive protein (CRP) level as a biomarker of inflammation, the Lung Health Study (LHS) examined the risk of all-cause and CVD mortality over 7 years of follow up in a COPD-specific cohort. The study found that, compared to the group with the lowest CRP level, the CVD mortality risk was 1.8 times higher for the highest CRP group. In the same study, the leading cause for hospitalization for this cohort of patients was CVD and the leading cause of mortality was lung cancer. Nearly half of all hospitalizations and 22% of all deaths were due to CVD. Lung cancer accounted for 33% of all deaths. Interestingly, only 8% of this study population died from respiratory failure.

In general, COPD is associated with an increased risk of lung cancer. Mild COPD (Gold stage 1) is associated with a 50% increase, moderate COPD (GOLD stage 2) 2.1 fold increase and severe COPD 2.7 fold increase, independent of the effects of smoking. Smoking further amplifies this risk and smoking cessation reduces this risk. However, smoking cessation never returns the risk to that of non-COPD subjects. Even if you have never smoked but you have developed COPD, your risk of lung cancer death is increased by 2.4 fold.

The race to being ‘developed’ has brought with it increased industrialisation, increased construction and increased consumption. In developed countries, the societal desire to stay ahead means ever more construction and consumption. Unfortunately, the inevitable consequence of all these activities is air pollution. As an individual, if you live in an environment with persistent air pollution, you are not able to stop these polluting activites around you. However, you can at least help yourself by not smoking. A small but worthwhile consolation.

With changing life styles, more and more individuals are complaining that they need more than 24 hours in a day to accomplish their daily needs - work, play and sleep, in that order! Consequently, sleep bears the brunt of the shortage of time and people end up sleeping less. So, apart from feeling a bit tired does sleeping less really matter?

A report from the University of Pittsburgh examined the relationship between sleep duration and the presence of the metabolic syndrome in 1214 individuals, aged 30 – 54 years, who participated in the University of Pittsburgh’s Adult Health and Behavior (AHAB) registry (Sleep 2008; 31: 635 – 643). There were 4 groups of participants based on sleep duration: < 6 hours (= very short sleepers), 6 – 6.99 hours (= short sleepers), 7 – 8 hours (reference group) and > 8 hours (= long sleepers).  Metabolic syndrome was defined according to the American Heart Association / National Heart Lung and Blood Institute’s (AHA/NHLBI) criteria as the presence of 3 or more of the following: (1) waist circumference > 102 cm in men or > 88 cm in women; (2) fasting serum glucose of ≥ 100 mg / dL or use of oral hypoglycaemic medication; (3) blood pressure of 130 mm Hg systolic, 85 mm Hg diastolic or higher or use of antihypertensive medication; (4) serum triglycerides of ≥ 150 mg /dL or use of hypertriglyceridaemia medication; (5) high-density lipoprotein (HDL) cholesterol of < 40mg / dL in men or < 50 mg / dL in women or use of medication for low HDL cholesterol. Twenty percent of the population was ‘very short sleepers’ and only 8% was ‘long sleepers’. When compared to the reference group, the odds of having the metabolic syndrome in short sleepers and long sleepers were increased between 48 – 83%.

A study from  Korea University looked at 4222 participants in the 2001 Korean National Health and Nutrition Survey and evaluated the relationship between sleep duration and metabolic syndrome [Int J Obes (Lond) 2008; 32: 1091 -1 1097]. The average amount of sleep per night, in hours, was categorized as ≤ 5, 6, 7, 8 and ≥ 9. Those who slept 7 hours per night had the lowest prevalence for metabolic syndrome. Individuals who slept ≤ 5 hours per night had the highest risk for metabolic syndrome, a 74% increased risk. Equally, those who slept ≥ 9 hours per night also exhibited an increased risk for metabolic syndrome. The prevalence of abdominal obesity and hypertension was highest in those who slept ≤ 5 hours per night while the prevalence of hyperglycaemia and hypertriglyceridaemia was highest in those who slept ≥ 9 hours per night.

Researchers from Japan and USA studied the impact of short sleep duration on incident cardiovascular disease (CVD; CVD events include stroke, fatal and non-fatal heart attacks and sudden cardiac deaths) and its possible interaction with nocturnal blood pressure (BP) in 1255 Japanese men and women with a mean age of 70.4 years (Arch Intern Med 2008; 168: 2225 – 2231). Short sleep duration was defined as < 7.5 hours. If the mean night time systolic BP exceeded the day time systolic BP, the individual would be classified as having a riser pattern of BP. Short sleep duration was found to be associated with a 68% increased risk of incident CVD. On comparing individuals with short sleep duration plus a riser pattern of BP to individuals with normal sleep duration plus a non-riser pattern, the risk of incident CVD is increased 4.43 times in those with short sleep duration plus a riser pattern.

Whenever I meet a patient who gives a history of loss of energy and tiredness, I invariably find that they have been burning the candle from both ends – staying awake longer in order to do more! In these cases, you really do not need to see a doctor; what you really need is to listen to your body. Your body is just like a motorcar, abuse it and it will break down quicker, look after it and it will merrily chug along for years.