October 5, 2011
Photo: Akshay Mahajan
Asbestos-related diseases (ARD) represent a growing global epidemic. Yet little is known about the current status of asbestos and ARD in Asia. Now, new research from the UNU International Institute for Global Health (UNU-IIGH) attempts to fill this void.
Growing awareness about the risks posed by asbestos — and the acquisition of asbestos-related diseases (ARD) data — has, in several cases from the region, correlated with a reduction in asbestos use. However, other Asian countries have been slow to learn these lessons.
Will the marked increase in asbestos use in Asia since the 1970s trigger a surge of ARD in the immediate decades ahead? What policy and public health measures can counterbalance a rise in asbestos-related diseases and mortality?
The World Health Organization (WHO) recognizes that asbestos is one of the most significant occupational carcinogens (cancer-causing agents). In 2006, it declared the need to eliminate the rise of ARD and asbestos use.
WHO estimates that, globally, some 107,000 deaths annually are caused by ARD; these include asbestos-related lung cancer, mesothelioma and asbestosis.
Despite gradually growing international awareness, at the regional level the analysis of asbestos use and ARD in Asia has been limited. The first regional-level discussions of the issue only took place in 2002, and a comparative understanding of the situation is patchy at best.
Ongoing data limitations make the task of filling the knowledge void on asbestos is Asia particularly challenging. ARD are known to be generally rare and difficult to diagnose. Furthermore, questions on data validity emerge in countries that have limited experience in diagnosing ARD. Similarly, under-reporting and inconsistent reporting of both asbestos use and ARD create additional barriers to obtaining a comprehensive picture: Of 47 Asian countries studied, 30 had data available for asbestos use only (not ARD), 15 countries had data available for both asbestos use and ARD mortality, and 2 countries only had data available for ARD mortality.
Nevertheless, using the indicators of per-capita asbestos use (measured in kilograms per capita per year) and age-adjusted mortality rates (AAMR, measured in cases per million population per year), recent groundbreaking research from the UNU International Institute for Global Health (UNU-IIGH) attempted to map the dimensions of Asia’s asbestos situation. Drawing on a comparative assessment of public data, this research compared the impact of asbestos in 47 selected Asian countries over the observation period of 1920 to 2007.
Overall, asbestos use in Asia from 1920 to 2007 totaled 55.5 metric tons, or 29 per cent of the world’s asbestos use. Asia’s proportion of global asbestos use increased significantly overall, from a 14 per cent share in 1920-1970 to 33 per cent in 1971-2000, then rising to 64 per cent in 2000 – 2007. In terms of ARD, 12.5 per cent of ARD deaths (or 12,882 deaths, or which 12,012 were mesothelioma) were recorded cumulatively in Asia.
During the observation period (1920 to 2007), most individual Asian countries (60 per cent) increased their asbestos use: Between 1920 and 1970 (period A), 5 countries recorded high values of asbestos use (greater than 1.0 kg/capita/year), while 13 countries recorded high values from 1970 to 2000 (period B). This spike in asbestos use was followed by a dip, back to 5 countries that recorded high values between 2000 and 2007 (period C).
Kazakhstan was the only county studied that maintained high values during all three periods. Cyprus and Lebanon both had high values for periods A and B and Kyrgyzstan, UAE, Thailand and Uzbekistan had high values for the two later periods (B and C). China, Thailand, India and Indonesia all increased their use of asbestos over the three periods.
Asia’s overall share of worldwide asbestos use is summarized in the chart below:
The chart highlights that prior to 1970, Asian countries only accounted for a minor proportion (14 per cent) of global asbestos use. This is reflected, at least partially, in the current situation for ARD, where only 17 of the 47 countries analysed in Asia recorded ARD. Only around 13 per cent of global ARD has occurred in Asia. (These figures are low for a region that, in 2000, represented 61 per cent of the word’s population.)
The situation is fluid, however, and has continued to change dramatically since Asian countries increased their share of world asbestos use from 1970 onwards.
Analysis of available data implies a linear correlation between the volume of a country’s past asbestos use and rates of ARD mortality (suggesting that recent and current usage will influence future ARD rates).
For example, peak asbestos use in Japan exceeded 2.0 kg/capita/year between 1970 and 1990, which was followed by a linear increase in ARD mortality. Asbestos use in the Republic of Korea peaked at just below 2.0kg/capita/year from 1975 to 1995, and this has also correlated with a rise in ARD. Singapore recorded a sharp peak in asbestos use around 1975 (to almost 4.0 kg/capita/year), followed by an almost four-fold increase in ARD mortality. China and India also have shown steep increases in asbestos use, but data on ARD is not available.
Among countries reporting ARD data for at least three years during the observation period, Cyprus, Israel and Japan had the highest rates of asbestos-related mortality.
“Countries reduced their asbestos use after realizing the burden of ARD. Although the reduction of asbestos use may correlate with a country’s own acquisition of ARD data, the ‘lessons’ of other countries are not easily learned.”
The rise in asbestos use in Asia generally correlates with rising asbestos-related mortality over time. As a general trend, the ARD epidemic curve follows the asbestos-use curve after several decades (where the initial rising of the presumed ARD curve coincides with the final waning segment of the asbestos use curve).
These correlations suggest that asbestos is likely to continue to take its toll on public health in Asia for years to come.
Several countries in Asia have moved to reduce (or ban) asbestos use after realizing the burden of ARD; however, the availability of national data plays a key role. Particularly since 2001, countries that had data available for both asbestos use and ARD have substantially reduced their asbestos usage. In contrast, countries where available data only covered asbestos usage (and not ARD) substantially increased their asbestos use over the same period.
Thus, although the reduction of asbestos use may correlate with a country’s own acquisition of national ARD data, countries that do not have this data available are slow to learn these important “lessons” from their neighbours.
These observations suggest that Asia’s increased asbestos use since 1970 will continue to take its toll in upcoming years. That is, countries will continue to experience ARD even after asbestos use decreases significantly, in a manner reflective of historical asbestos use.
An accurate sketch of regional trends, however, is limited by data availability. In particular, it is highly unlikely that ARD are absent in countries such as China and India, both of which have used large volumes of asbestos but have not reported/do not report the related numbers. (In China and India, the large volume of asbestos use is also diluted by their large populations, i.e., per capita rates remain moderate.) The moderate per capita use of asbestos in populous countries, therefore, cannot be overlooked.
What political measures are Asian countries taking to counter the damage caused by asbestos use? Has weak political will to improve the situation, combined with ongoing limited resources to diagnose ARD, compounded an ARD epidemic?
Public sentiment has a role to play in motivating political will. Japan, which was a major asbestos user, experienced the Kubota Shock (media exposure of a cluster of ARD victims) in 2005 and, as a result, adopted a total ban on asbestos in 2006. Similarly, the Republic of Korea also promulgated a ban, in principle, in 2006 and imposed a total ban in 2009, after recognizing a surging number of ARD cases. Momentum is gradually growing and, at present, several South-East Asian countries are also at various stages of considering a ban.
The International Labour Organization’s (ILO) Asbestos Convention (1986) commits signatory states to protect workers from potentially harmful occupational asbestos exposure. In Asia, ratification of this important ILO convention is significantly lower than the global average (just 6 per cent of Asian countries — namely Cyprus, Japan and the Republic of Korea are signatories — compared to 17 per cent of countries globally). The percentage of Asian nations that have implemented a total asbestos ban, however, is more on par with the global average (28 per cent of Asian countries, compared with 30 per cent of countries worldwide).
The adoption of such bans can contribute to a significant reduction in ARD mortality.
As a practical recommendation, Asian countries should look to ban asbestos as soon as possible, minimize exposure and ratify the ILO convention. No matter what is done, however, a surge of ARD in Asia should be anticipated in the coming decades. Asian countries, therefore, should not only cease asbestos use but also prepare for an impending epidemic.
This article is based on G.V. Le, K. Takahashi, E.-K. Park, V. Delgermaa, C. Oak, A. Munir. and S.M. Aljunid, “Asbestos use and asbestos–related diseases in Asia: past, present and future,” Respirology (2011), 16, pp. 767–775.