The research question the paper attempt to study is to assess the change in the prevalence of overweight and obesity among Nicobarese adults from 1960s to 1999 (by adopting the WHO recommendations for classification of overweight and obesity).
Such a research question warrant researchers’ attentions because overweight and obesity are increasingly becoming serious issues in both developed and developing country. Besides, obesity can cause different types of diseases. Many of these diseases are life-threatening.
The key background literatures employed in this study are as follow. Firstly, there are many researchers found that a trend of obesity can be observed around different part of the world. Hodge et. al. (1994) found that obesity trend can be seen in Samoa from year 1978 to 1991. Then Hodge et. al (1996) discovered that obesity trend can be seen in Mauritius from year 1987 to 1992. Besides, Tremblay et. al. (2002) also found that obesity trend can be seen in Canada from year 1981 to 1996. Similarly, Ge (1997) found that obesity trend can be observed in China. Furthermore, Bharati et. al (2007) found that obesity trend can be observed among Malay and Indian women. Obesity can be harmful to heath. For this, Lew et. al (1979) argued that those obese have an elevated risk from all cause mortality. Similarly, Sarkar (n. d.) and Sahani (2004) found that overweight and obesity are prevalent in both non-tribal and tribal group (that are embracing modern living lifestyle).
A review of the background literature indicates that obesity can be found in many countries, regardless of the religion, culture or geographical locations. A rising trend of obesity can be found in both urban and non-urban people. Not only is that, obesity can be found in both non-tribal and tribal group as well. All the previous indicate that obesity is becoming a more common and prevalent issues in modern society around the world.
Thus, the authors believe that their study able to contribute by carrying out a study that focus on the weight and obesity among Nicrobarse adults (from Nicobar Island in India), and from that, enable them to understand the degree of increased level of vulnerability of population at that Island, from the year 1960s to 1999.
Overall, it is found that the hypotheses selected are relevant because such a study take a more in-depth analysis on the obesity issues in a segment of population in one of the island from India. Such a research is not published before. After the obesity trend in that particular segment of people can be understood, better strategies or policies can be implemented to take care of the health of these people. Else, policy makers or people from that island may not understand the degree of seriousness of the obesity issues they are facing.
In order to study the obesity issues in Nicobar Island, the following steps are being carried out. Firstly, in 1960s, a total of 774 individuals are selected from the population of Nicobarese adults are selected. The following of these adults are being measured: (a) height (cm), (b) sitting height (cm), and (c) weight (cm). The age and gender of the participants on the research are also recorded. Then, in 1999, a total of 484 individuals are selected from the population of Nicobarese adults are selected. The BMI (i.e., body mass index), calculated as weight/ height2 for these people are measured. The age and gender of the participants on the research are also recorded. Subsequently, the mean and standard deviation of these variables are calculated: (a) height (cm), (b) sitting height (cm), (c) weight (cm), and (d) BMI. (Remark: these variables are also known as the anthropometric variables). In order to test if there are statistically significant differences between the anthropometric variables for these two groups of sample (i.e., one sample from 1960s, and another from 1999), t-test was conducted. Besides, odd ratio has also been computed via logistic regression methods, in order to understand the degree of getting overweight between these two periods. SPSS was used for analysis. All statistical tests are conducted at a 5% significance level.
To investigate if the research design implemented is proper, several aspects of the methods used in research design are studied. A discussion on the research design is presented and summarized in Table below.
In this section, the question that what measures have been taken to control bias and random variation and why? For this, this paper is relatively silent on the measures used to control bias and random variation. However, it is reasonable to expect that random sampling processes are used. Besides, the paper is also relatively silent on the methods used to control bias in the research design. To a certain degree, this means that the research findings may be subjected to unforeseen bias, which will affect the accuracy and reliability of the research results.
In this section, the question that if the measures adequate and appropriate will be discussed. Firstly, it is found that the sample size selected is large enough so make the results reliable. For a t-test, 30 randomly selected samples are sufficient to conclude that the results from the test are valid (McNeil, 1990). Indeed, to go for extra miles, a total of 60 sample selected will be generally perceived as adequate. For the research, 774 individuals are selected in 1960s, while 484 individuals are selected in 1999. The huge sample size used is indeed sufficient.
In this section, the design details about which decisions had to be made will be listed. The relevant justification for these decisions will be discussed as well.
Firstly, to calculate the obesity level, a measurement scale on the obesity must be used. In this research, those anthropometric variables can be used to measured obesity level. This is justifiable because to select the standard used to measure obesity, the BMI standard recommended by WHO is utilized. The standard adopted by WHO is popular, and generally accurate, and thus can be used in the research design.
Secondly, researchers must make decision on the sample size. As discussed above, the sample size selected is adequate. The rationale for this is sample size must be large enough, so that the research findings can be concluded as statistically significant.
Thirdly, the proper statistical tests to be used to analyze the data collected must be decided. In the study, statistical tools/ concepts used are: (a) t-test, and (b) odd ratio (from logistic regression). The justification for this is that t-test is widely used to test the means between two samples, while odd ratio can be used to understand the degree of getting overweight between the samples (Bell, 2005).
The presentation of research findings is clear and relevant for data analysis purposes. A total of four tables as well as one figure are presented. The details about these Tables and the figure are discussed as follow. In the article, Table 1 presents the statistical properties/ characteristics of the data (i.e., anthropometric variables) under studied. The results obtained from t-test are also presented. Three set of data are presented: (a) men, (b) women, and (c) total. This table clearly shows that there are significant differences between samples collected in 1960s to those from 1999. Then, Figure 1 present graphical representation of the percentage of overweight and obesity among the two groups of sample. A glance at the chart indicates that the obesity issues had increased dramatically during the period under researched. Besides, Table 2 consolidates the research, and combines all of the anthropometric variables into standard BMI benchmark. Again, t-test indicates that there are significant differences between samples collected in 1960s to those from 1999. Furthermore, Table 3 shows the distribution of BMI gradation by sex and age group. This table provide better picture for readers that are interested to analyze which segment of adults under studied had suffer greater degree of obesity issues. It enables readers to carry out better analysis in greater depth. Lastly, Table 4 is meant to supplement Table 3 above. Odd ratios for the data, separated by sex and age group are presented.
Overall, the presentations of results are clear and accurate. The groups (primarily divided by age and sex), and the years of study are stated clearly. The measurement scale and the respective figures obtained from statistical simulation are presented. All of the tables and figure are labeled clearly. The significance level are also calculated and presented. All of the data are presented in a way to ease analysis and interpretation by readers.
Based on the findings, it is found that the authors had derived several concluding remarks as follow: It is obvious that obesity problems are becoming more prevalent among people in Nicobar Island. Besides, it is also found that the possible trend responsible for such issues is probably due to political stability in the Asian region. When politics are stable, economic growth brings along many changes to people living standard and lifestyle. The authors also concluded that traditionally, people from Nicobar Island had a more low-fat oriented diet, while in the recent decades; their diet had changed to one of higher-fat diet. It is pointed out that the traditional foods consumed by Nicobarese are: starchy pulp, coconut, banana, yam, taro, and tubers. Today, these Nicobarese consume: rice, wheat flour, pulses, biscuits, sugar, powder milk, and oil. Besides, the changes of types of physical activities also contribute to the obesities issues among those Nicobarese. It is pointed out that the traditional activities of Nicobarese are: horticulture, fishing, raring of pigs and fowls, repairing canoes, as well as making baskets, mats, and wooden iron spears. Today, most of them are working from an office.
Of the many conclusions presented by authors, only the fact that “It is obvious that obesity problems are becoming more prevalent among people in Nicobar Island” can be supported by the data or research results derived from this research study.
The rest of the conclusions, are primarily more ‘discussion’ in nature. The reason is that there are no primary data or findings to support if those identified factors (namely the change of dietary habits, as well as the changes in the forms of physical activities) are contributing to the obesity issues among people staying on the Nicobar Island. In fact, it is noted that the authors form such conclusion by referring to the findings from other studied performed by other researchers. Effectively, the findings from other studies are borrowed to combine with the existing data and research results found to form more meaningful conclusions. Thus, secondary data or findings had been used.
Ideally, the authors should perform more research to understand if the changes in living standard, those ultimately causing changes in dietary habits and different forms of physical activities are indeed the main factors contributing to the obesity issues among population staying on the country. This will then provide most convincing research findings that the root cause causing the obesity issues are identified.
However, we cannot conclude that the conclusions made by authors are not valid. This is because many of the findings from previous literature (which argued that changes in dietary habits and different forms of physical activities are contributing to the obesity issues) are theoretically sound. These sorts of researches are abundant, making them highly reliable information to be relied upon. Many of the literature are also published in reputable journals, and thus making them dependable and trustable. Besides, a review of these literature indicate that the findings are pretty consistent, whereby eating more fattening food and having less exercise can contribute significantly to obesity issues. All this make the conclusions argued by the authors to become valid and dependable.
Some weaknesses of the report are identified: (a) not suggesting possible solutions, (b) not proactively criticize the weaknesses or strengths of the research methods used, and (c) not specifying the methods used to select the samples, and how to control and prevent any bias from happening in the sampling process.
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