Asthma victims: added cause for anxiety
DESPITE strides in asthma treatment, the incidence of the disease and deaths due to it are escalating. Researchers now feel that growing industrialisation and pollution could well be responsible for this increase worldwide.
Every year in USA alone, some 4,000 asthma victims die and another 500,000 are hospitalised. In 1977, some 1,700 people died from asthma, and the figure had doubled by 1984. The increases in recorded mortality are also related to changes in the classification of the causes of death and the declining access to health care in USA, particularly among poor urban blacks.
In India, there have been very few surveys on the prevalence of asthma, but indications are that the number of patients has increased over the years. In the 1960s, according to a study undertaken by R Vishwanathan, then director of the Vallabhbhai Patel Chest Institute in Delhi, about 3 per cent of the adult population suffered from bronchial asthma. Now, S K Chabra, chest physician and lecturer at the department of cardiorespiratory physiology at Patel Chest Institute, says about 7 per cent of the adult population in India is probably asthmatic.
The reasons for the increased incidence are obscure, but about half the cases in the UK, for example, are linked to allergies. The prevalence of these is rising and is linked to greater industrialisation. Modern Western homes are an ideal breeding ground for house dust mites, a known cause of asthma. Pets, house plants and central heating provide a perfect environment for these mites to grow. Other cases, not explained by allergies, are reportedly related to pollution, smoking and, possibly, childhood viruses.
Smoke and dust are known to trigger asthmatic symptoms. In animal tests, exposure to pollutants like ozone, nitrogen dioxide and sulphur dioxide produced reactions seen in asthmatics. Many cases of asthma reported in the West, according to Chabra, have developed due to exposure to pollutants more than 20 years ago. In India, with increasing pollution, asthma cases are expected to increase in the next 20 years. For the first time in India, a long-term study to determine the effects of vehicular pollution on traffic police is being initiated by doctors at the Patel Chest Institute.
Doctors are struggling to discover the optimal treatment for this debilitating disease. Beta2-agonist bronchodilators were once considered a wonder drug as they are extremely powerful and side-effects are rare. But they only treat the symptoms and not the underlying inflammation. Two recent studies -- in Canada and in New Zealand -- indicate that bronchodilators may actually be doubling the risk of death from asthma as patients with a deteriorating condition tend to rely on them too much and fail to tell their doctors about their worsening condition.
The underlying condition of moderate and severe asthma needs to be treated with both bronchodilators and corticosteroids, experts say. Steroids reduce the inflammation, but they have potential side effects like Cushing's Syndrome, which results in moon-faced features, hunched shoulders and increased hair growth. In children, they also inhibit physical growth. Doctors usually prescribe low doses to treat asthma without complications. In the UK and Sweden, doctors are more inclined to prescribe inhaled steroids, which account for 43 per cent of the asthma treatment market. In USA, however, the market share of inhaled steroids is only 11 per cent, but the reluctance to prescribe them is beginning to change.
Drug companies are trying to develop alternative therapies, pouring hundreds of millions of dollars into asthma research, including the development of potent steroids with a wider safety margin. The disease is big money. In 1990, asthma cost the US economy $6.2 billion, equivalent to 1 per cent of all expenditure.