Asthma: Is the Outlook Better for Older Males?

"Doc, will I outgrow my asthma?"

This question is frequently asked by patients and parents in my office. I usually respond by saying: "Clinical research has uncovered genes that are the likely cause of asthma. We do not outgrow our genes but the activity of our genes may vary over time. We may therefore have remission periods which may last months to years."

This means that after a period of being asthma symptom free, sometimes several years, asthma attacks may come back.

Reuters Health recently reported results of a study (American Journal of Respiratory and Critical Care Medicine [AJRCCM], Aug. 2008) which concluded that boys were more likely than girls to outgrow asthma.

Over a thousand children between 5 and 12 years of age, with mild to moderate asthma were studied. Methacholine challenge (MC) was conducted annually over a period of 9 years. MC is a test that measures the level of hyper-reactivity or twitchiness of the lung airways. All asthmatics have abnormally twitchy airways. This tendency is also referred to as airway responsiveness (AWR).

In the study both males and females had decreased AWR over time as they approached 11 years of age. But starting around puberty, the girls surpassed the boys in AWR.

Boys and Women Suffer Worse Asthma Than Men and Girls

For many years asthma research has highlighted the observation of male predominance of severe asthma in the first 15 years of life but a flip-flop to females with higher severity in adulthood.

Some researchers have speculated the difference between the sexes being related to a delayed maturation process of the lung airways in males in the early years. Others have postulated hormonal influences such as the impact of increased estrogen in females, or testosterone in males. No one really knows why there is such a difference in asthma severity between males and females.

Inquiring minds might ask: Are death rates higher for women too?

The Centers for Disease Control and Prevention (CDC) has mortality data for asthma that spans the years from 2001-2003 (most recent analysis). During this period of time female asthmatics had death rates of 2.3 per 10,000 patients with current asthma whereas males had 1.8 deaths per 10,000. I should point out that death rates were relatively small for all asthma patients under 18 during this period.

Furthermore male at-risk based death rates (at risk = established asthma patients) were higher than female until the age of 65. But 50% of asthma deaths occurred in people over age 65, the women out-numbering the men (female deaths- 2,693, male deaths- 1,517).

How should the AJRCCM study impact current asthma management?

The study reviewed in Reuters Health basically supports and further defines a characteristic of asthma that has been established for several years. The fact that persistent AWR may be the cause of more severe asthma and perhaps increased risk of death in adult females is quite important.