The Correlation Between Gross Domestic Product and Reported Cases of Malaria in India (1999-2011)

Abstract: Malaria is a life-threatening disease that affects millions worldwide due to parasite-infected mosquitoes. Following the bite, the parasite can infect its new host by attacking the excretory system. Malaria morbidity and mortality commonly affect and effect many parts of Africa, the Middle East and Southeast Asia. Due to the high numbers it affects, malaria has become a major public health issue since its discovery in 1880. One of the many countries where malaria has become a major burden is India - whose malaria rate has contributed significantly to the worldwide problem. In this study, the relationship between number of reported cases of malaria and gross domestic product (GDP) of India are examined closely, resulting in a noticeable correlation factor of 0.4533. Further examination of India's malaria rate and GDP are also done by comparing it to the United States, Indonesia and Canada.

Introduction: Malaria has had a rich history since its inception in 2700 BCE in China and later widely found in ancient Greek literature. Upon a discoveries by Charles Louis Alphonse Laveran and Ronald Ross, the parasite causing malaria and that these parasites could be transmitted by mosquitoes respectively, the uphill battle towards a cure began. 1 Malaria can occur after being bitten by an infected female mosquito. Infected protists from the mosquito's saliva travel into the new host's circulatory system, ultimately ending up in the human liver, where further maturation and reproduction occurs. Common symptoms include fever, headache, nausea, myalgia and diarrhea. If not treated, these symptoms can lead to death.2 Statistics have shown that 80% of malaria cases are concentrated in seventeen countries, as illustrated by Figure 1.

1

Figure 1: A global illustration of the concentration of cases amongst seventeen countries affected by malaria.

Because malaria has become a common public health concern for countries within Africa, the Middle East and Southeast Asia, there has been a growing initiative to control and eradicate the disease. Organizations such as the World Health Organization (WHO) have made malaria prevention and control key global topics. In India, the highest incidence of malaria occurred in the 1950s, with approximately 75 million cases reported within a span of a decade. Since then, there has been a steady decline with the exception of a resurgence in 1965. 4 As of data collected from WHO from 2011, the number of cases reported is currently fixed around one million, with a current risk status of "moderate".2 Since 1999, India's annual GDP has positively increased from $1,800 (PPP - per capita, US$) to $3,700 in 2011.5 The decline of malaria cases in India can possibly be attributed to the increase in the country's increase in GDP. Similar studies have also been done by Gallup and Sachs in "The Economic Burden of Malaria" as well as a group of public health experts in "Malaria in India: The Center for the Study of Complex Malaria in India".3,4 This specific study aims to examine these two factors in India and their correlation with each other, as well as its overall relationship with other countries. Thus, India's annual malaria rate and GDP are compared with the United States'. However, because these two countries have such contrasting statistics - the United States has an annual GDP three times that of India and an almost non-existent malaria risk status - two other countries are brought into consideration for the purpose of running a valid t-test. For this purpose, a country with a similar malaria relative frequency as India was chosen and a country with similar annual GDP as the

2

United States was chosen. With these new parameters, Indonesia and Canada were chosen. Thus, for reported cases of malaria, the following was hypothesized:

H0: The reported malaria rate for Indonesia and India is the same. H1: The reported malaria rate for Indonesia and India is different.

And for annual GDP, the following was hypothesized: H0: The GDP for Canada and the United States is the same. H1: The GDP for Canada and the United States is different.

Methodology:

CorrelationTo further examine the relationship between India's GDP and malaria rate, the following data was obtained and generated:

Year

India GDP (PPP - per capita, US$)

India Malaria (# of reported cases) Total Population Relative Frequency Percentage

1999 1800 2280000 997515000 0.00228568 0.2285679912000 2200 2030000 1029991000 0.001970891 0.1970891012002 2540 1840000 1045845000 0.001759343 0.1759342922003 2900 1870000 1049700000 0.001781461 0.1781461372004 3100 1920000 1065071000 0.001802697 0.1802696722005 3400 1850000 1080264000 0.001712544 0.1712544342006 3800 1785109 1095352000 0.001629713 0.1629712642007 2600 1508927 1129866000 0.001335492 0.13354922008 2900 1532497 1147996000 0.001334932 0.1334932352009 3200 1563574 1166079000 0.001340882 0.1340881712010 3500 1599986 1173108000 0.001363886 0.1363886362011 3700 1310367 1189173000 0.001101915 0.110191452

Table 1: Data collected by the World Health Organization and Index Mundi from 1999-2011.

3

Figure 2: A scatter plot depicting the relationship between annual GDP and relative frequency of Malaria in India from 1999-2011, with a correlation factor of 0.45333.

Analysis of Malaria Rate To study the relationship between Indonesia and India's malaria rate, the following data was obtained:

YearI ndonesia Malaria (# of

reported cases) Total Population Frequency Percent2006 1150600 245452700 0.004687665 0.4687664872007 1149000 234694000 0.004895737 0.4895736582008 1142960 237512400 0.004812212 0.4812211912009 1085000 240271500 0.004515725 0.4515724922010 1067000 242968300 0.004391519 0.4391519392011 1052000 245613000 0.004283161 0.428316091

Table 2: Data collected by the World Health Organization from 2006-2011 for Indonesia.

4

YearI ndia Malaria (# of

reported cases) Total Population Frequency Percent2006 1785109 1095352000 0.001050439 0.1050438582007 1508927 1129866000 0.001016935 0.1016934752008 1532497 1147996000 0.000995613 0.0995613232009 1563574 1166079000 0.000930469 0.0930468692010 1599986 1173108000 0.00090955 0.0909549672011 1310367 1189173000 0.000884648 0.088464841

Table 3: Data collected by the World Health Organization from 2006-2011 for India.

2005 2006 2007 2008 2009 2010 2011 20120

0.001

0.002

0.003

0.004

0.005

0.006

f(x) = − 3.47500180733012E-05 x + 0.0707600201884476R² = 0.975786584588255

f(x) = − 0.000109475953935346 x + 0.224480123241555R² = 0.720498815047931

Malaria Frequency

IndonesiaLinear (Indonesia)IndiaLinear (India)

Year

Freq

uenc

y of

Rep

orte

d M

alar

ia C

ases

Figure 3: A scatter plot depicting the decline in frequency of malaria in India and Indonesia from2005-2011.

5

Using the data from Tables 2 and 3, a t-test was used to test the hypothesis at a 1% level of significance.

t-Test: Two-Sample Assuming Unequal Variances

Variable 1 Variable 2Mean 1107760 1550076.667

Variance 2012723200 23475276263Observations 6 6Hypothesized Mean Difference 0df 6t Stat -6.786425012P(T<=t) one-tail 0.000250381t Critical one-tail 1.943180274P(T<=t) two-tail 0.000500761t Critical two-tail 2.446911846

Table 4: Results from a t-test assuming unequal variances, with variable 1 representing Indonesia and variable 2 representing India.

Analysis of GDP To study the relationship between the United States and Canada's GDP, the following data was obtained:

Year Canada GDP - (PPP - per capita, US$)1999 233002000 248002002 294002003 298002004 315002005 339002006 356002007 386002008 391002009 381002010 394002011 41100

Table 5: Data collected from Index Mundi for Canada from 1999-2011.

6

Year US GDP (PPP - per capita, US$)1999 339002000 362002002 376002003 378002004 401002005 416002006 440002007 458002008 469002009 460002010 472002011 49000

Table 6: Data collected from Index Mundi for the United States from 1999-2011.

Figure 4: A scatter plot depicting the increase in annual GDP for Canada and the United States from1999-2011.

7

Using the data from Tables 5 and 6, a t-test was used to test the hypothesis at a 1% level of significance.

t-Test: Two-Sample Assuming Unequal Variances

Variable 1 Variable 2

Mean 33716.67 42175Variance 35394242 24922045Observations 12 12Hypothesized Mean Difference 0df 21t Stat -3.77275P(T<=t) one-tail 0.000559t Critical one-tail 1.720743P(T<=t) two-tail 0.001117t Critical two-tail 2.079614

Table 7: Data collected from Index Mundi for the United States from 1999-2011.

Results: As demonstrated in Figure 2, there is indeed a noticeable correlation between India's annual GDP and number of reported malaria cases, with a r2 value of 0.4533. As suspected, as the annual GDP increased, the reported malaria cases decreased, therefore confirming the correlation between these two factors. Perhaps inclusion of more data over a longer period would result in an even stronger correlation factor. Due to time constraints and a limited amount of resources, a period of ten years is utilized.

Following the comparison of India's annual GDP and malaria rate, a t-test was conducted separately for malaria rate (India and Indonesia) and annual GDP (United States and Canada). As mentioned in the introduction, because of the drastic differences between India and the United States, special measures were taken in order to obtain valid results. In order to run a t-test for these two countries, the country chosen must either have a similar GDP or a similar malaria rate. As a result, Indonesia was paired with India and United States was paired with Canada.

For the malaria rate, each country's annual malaria frequency was graphed (Figure 3) and found to both demonstrate an annual decline. T-test results for both 1 and 2 tails at the 1% significance level resulted in very small p-values of 0.000250380692606768 and 0.000500761385213536 respectively. Such small p-values lead to rejection of H0 and acceptance of H1. The malaria rates for India and Indonesia are not the same, although both are considered to have "moderate" malaria risks by WHO.

Similarly, a t-test was conducted for the annual GDP of the United States, which was paired with Canada. The annual GDP for both countries were graphed (Figure 4) and found to both have increasing annual GDPs. The t-test results in Table 7 for both 1 and 2 tails at the 1% significance level resulted in very small p-values of 0.000558575917115377 and

8

0.00111715183423075 respectively. Like the malaria rate, the small p-values for annual GDP lead to rejection of H0 and acceptance of H1. The annual GDPs for Canada and the United States are not the same, although both are considered by Index Mundi to have similar economies.

Conclusion: The effects of malaria can lead to devastating levels of morbidity and mortality for those countries that are affected. Due to organizations such as WHO, a higher emphasis is put on education and immunization to prevent further outbreaks from occurring. Based on the information compiled for this study, the correlation between India's GDP and malaria rate is strong. Since 1999, India's economy (GDP) has steadily increased, leading to more money put towards public healthcare. According to the most recent GDP statistics from India, the amount spent on healthcare will rise from 1.4% to 2.5%. This bodes well for the communities that have been heavily affected by malaria. More money spent on healthcare will lead to more immunizations for young children (who are the most at risk for infection), insecticide-treated nets and insecticide sprays. Compared to the United States (where malaria has become almost non-existant), which spends approximately 7% of its GDP on healthcare, India is very far behind.6 However, with more of the country's GDP spent on public health, positive steps are being taken to ensure eradication of malaria.

_____________________________________________________________________________

1. http://www.cdc.gov/malaria/about/history2. http://www.who.int/features/factfiles/malaria/en3. http://www.ncbi.nlm.nih.gov/books/NBK2624/4. http://www.thereadgroup.net/wp-content/uploads/Das-et-al-India-ICEMR-2012.pdf5. http://www.indexmundi.com/g/g.aspx?c=in&v=676. http://www.indianexpress.com/news/healthcare-spend-to-rise-to-2.5--of-gdp/918380/

9