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Ecology of Food and Nutrition Publication details, including instructions for authors and subscription information: http://www.tandfonline.com/loi/gefn20
Body Mass Index and Blood Pressure among Men of Three Ethnic Groups of Darjeeling, West Bengal, India a
Sudip Datta Banik a
Department of Human Ecology, Cinvestav-IPN, Unidad Mérida, Yucatan, Mexico Published online: 15 Apr 2014.
To cite this article: Sudip Datta Banik (2014) Body Mass Index and Blood Pressure among Men of Three Ethnic Groups of Darjeeling, West Bengal, India, Ecology of Food and Nutrition, 53:3, 256-272, DOI: 10.1080/03670244.2013.814462 To link to this article: http://dx.doi.org/10.1080/03670244.2013.814462
PLEASE SCROLL DOWN FOR ARTICLE Taylor & Francis makes every effort to ensure the accuracy of all the information (the “Content”) contained in the publications on our platform. However, Taylor & Francis, our agents, and our licensors make no representations or warranties whatsoever as to the accuracy, completeness, or suitability for any purpose of the Content. Any opinions and views expressed in this publication are the opinions and views of the authors, and are not the views of or endorsed by Taylor & Francis. The accuracy of the Content should not be relied upon and should be independently verified with primary sources of information. Taylor and Francis shall not be liable for any losses, actions, claims, proceedings, demands, costs, expenses, damages, and other liabilities whatsoever or howsoever caused arising directly or indirectly in connection with, in relation to or arising out of the use of the Content. This article may be used for research, teaching, and private study purposes. Any substantial or systematic reproduction, redistribution, reselling, loan, sub-licensing, systematic supply, or distribution in any form to anyone is expressly forbidden. Terms & Conditions of access and use can be found at http://www.tandfonline.com/page/termsand-conditions
Ecology of Food and Nutrition, 53:256–272, 2014 Copyright © Taylor & Francis Group, LLC ISSN: 0367-0244 print/1543-5237 online DOI: 10.1080/03670244.2013.814462
Body Mass Index and Blood Pressure among Men of Three Ethnic Groups of Darjeeling, West Bengal, India SUDIP DATTA BANIK Downloaded by [University of South Florida] at 10:09 14 October 2014
Department of Human Ecology, Cinvestav-IPN, Unidad Mérida, Yucatan, Mexico
This study was undertaken from 2009–2011 to understand the association between body mass index (BMI) and blood pressure (BP) (systolic or SBP and diastolic or DBP) among randomly chosen men, aged 30 to 59 years, of three endogamous communities in Darjeeling, West Bengal, India: Dhimal (n = 88), Mech (n = 71), and Rajbanshi (n = 83). Analysis of variance was applied. Remarkable rates of BMI-based undernutrition (chronic energy deficiency or CED) were recorded among Dhimals (31%) and Rajbanshis (18%). Notable prevalence of overweight (20%) was recorded among men of Mech community. None were found to be obese in three samples. Mean SBP and DBP were found to rise consistently at levels of BMI (undernutrition, normal, and overweight). BMI was observed to rise consistently at levels of blood pressures (normotensive, prehypertensive, and hypertensive). Among Mech, this pattern was found to be more conspicuous. DBP was found to be more sensitive with changes of BMI in men. KEYWORDS hypertension, normal, overweight, undernutrition
Blood pressure (BP) is an important physiological factor, sensitive to socioeconomic conditions, urbanization, activity patterns, diet, body weight and fat, and other physical and cultural determinants in addition to its genetic predisposition, familial association, and ethnic background (Kearney et al. 2004; WHO 1996). BP is one of the important indicators of several cardiovascular complications (Canoy et al. 2004). Nutritional status is an important factor Address correspondence to Dr. Sudip Datta Banik, Department of Human Ecology, Cinvestav–IPN, Unidad Mérida, Antigua Carretera a Progreso km 6., Mérida 97310, Yucatán, Mexico. E-mail: [email protected] 256
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that determines blood pressure. In epidemiological research, understanding the relationship between body mass index (BMI) and BP is important. A positive correlation between BMI and BP had been reported from adult Caucasian populations (Tesfaye et al. 2007). BMI had been observed to be related with BP among adults in Sweden (Henriksson et al. 2003), China (Zhou 2002), Pakistan (Khan et al. 2008), and India (Das, Sanyal, and Basu 2005; Desmukh et al. 2006; Gopi Chand and Rao 2007; Gupta 2004; Gupta et al. 2007; Kusuma, Babu, and Naidu 2004; Reddy, Reddy, and Sudha 2010; Santhirani et al. 2003). In West Bengal, India, especially in urban and semi-urban societies, increased BP was a major health concern for adults (Chakraborty, Bose, and Bisai 2009; Datta Banik 2007; Ghosh and Bandyopadhyay 2007). The risk of hypertension was relatively lower in adults who had normal BMI (< 24 kg/m2 ) in comparison with overweight individuals in Uzbekistan (Mishra 2005). In developing countries, a higher risk of cardiovascular mortality among lean individuals had been documented (Goldbourt et al. 1987; Stamler et al. 1991; cf. Tesfaye et al. 2007). A high rate of undernutrition was found among men in Ethiopia (36.7%), Vietnam (32.5%), and Indonesia (14%). In that study, the prevalence of hypertension was found to be higher in first and fifth quintiles of BMI that suggested higher cardiovascular risk in individuals who were suffering from either undernutrition or overweight (Tesfaye et al. 2007). In some adult tribal populations of India, morbidity increased in males due to the co-existence of high rates of underweight (45.3%) and hypertension (systolic BP 15.2%, diastolic BP 25.5%) (Kapoor et al. 2012). High BMI, low physical activity, non-vegetarian diet, and consumption of alcohol and tobacco were associated risk factors for increasing rate of hypertension in adults of North India (Gupta et al. 2012). Similar reports from rural and tribal populations, on BP in relation to nutritional status, especially from Darjeeling District of West Bengal, India were not available. Moreover, data from endogamous communities of Darjeeling, like Dhimal, Mech, and Rajbanshi, were very few (Datta Banik 2011; Datta Banik et al. 2007; Datta Banik, Basu et al. 2008a; Datta Banik, Jana et al. 2008b; Datta Banik, Bhattacharjee, et al. 2009b). The principal objective of this study was to investigate the relationship between BMI-based nutritional status and BP (systolic and diastolic) among men of Dhimal, Mech, and Rajbanshi communities at Naxalbari in Darjeeling district of the state of West Bengal in India.
MATERIALS AND METHODS Dhimals were found in hamlets called “Dhimal basti” or “Dera”: Ketugaburjot and Siuborjot. Mech hamlets were Nehaljot (Tarabari) and South Kotiajot. Rajbanshis were found in hamlets namely Ketugaburjot and Kumarsinghjot.
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These villages at Naxalbari were located around 35 km from Siliguri town in Darjeeling District, which is approximately 580 km towards the north from Kolkata (Calcutta), the provincial capital of West Bengal. The samples were free from any selection bias. Participants were not chosen on the basis of bodily structure and proportion. The sample included apparently healthy men (age range between 30 and 59 years) of three communities (Dhimal, Mech, and Rajbanshi). The survey was carried out between July 2009 and November 2011 in the villages at Naxalbari block and Maniram Panchayat in Darjeeling district. Block and Panchayat were statutory bodies of the Government. Censuses of those populations at Naxalbari were recorded through household survey. Randomly selected individuals constituting the sizes of three samples (Dhimal = 88, Mech = 71, Rajbanshi = 83) exhibited similar proportionate representations of the respective populations at Naxalbari with respect to the studied age groups. Dhimal, Mech, and Rajbanshi represented 36.4%, 29.3%, and 34.3% of the total individuals (N = 242) in the study, respectively. The sample (N = 242) covered almost 85% of the total number of men (aged 30 to 59 years) in 10 hamlets of these three communities at Naxalbari. Numbers of participants in age-groups, representing three ethnic groups, were: 30–39 years (Dhimal = 32, Mech = 32, Rajbanshi = 21); 40–49 years (Dhimal = 30, Mech = 28, Rajbanshi = 33); 50–59 years (Dhimal = 26, Mech = 11, Rajbanshi = 29). Anthropometric and physiometric data were collected from the participants who reported not to be suffering from any chronic or acute diseases three months before the survey. None of the participants suffered from malaria, which was very common and highly prevalent in that region. Only those individuals who were suffering from any acute or chronic diseases (e.g., malaria, tuberculosis, hepatitis, cough and cold with fever, skin infections) and had physical handicaps or remained absent during the survey, could not be included in the study; eight individuals were excluded based on such criteria. All anthropometric measurements of lightly-clothed participants were taken by the author, using standard anthropometric techniques (Lohman, Roche, and Martorell 1988). Height (HT in centimeter) and body weight (BW in kilogram) were taken to the nearest 0.1 cm and 0.5 kg, respectively, using standard Martin’s anthropometer and weighing scale (Doctor Beliram and Sons, New Delhi, India). BMI was computed as body weight (kg) divided by squared height (meter) (WHO 1995). Cut-off values of BMI for adults (WHO 1995) determining levels of nutritional status were: undernutrition (< 18.45 Kg/m2 ), normal (18.50 - 24.99 Kg/m2 ) and overweight (> 25.00 Kg/m2 ). BMI cut-off values for Asian people, recommended by the WHO expert consultation (WHO 2004), displayed similar distributions in the present data. Physiometric measurements of systolic (SBP) and diastolic (DBP) blood pressures (mmHg) were measured by standard mercury sphygmomanometer (Diamond, New Delhi) following standard
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protocol (Pickering et al. 2005). Based on blood pressure, participants were classified as normal (SBP ≤ 120 mmHg, DBP ≤ 80 mmHg), prehypertensive (SBP 120 < 140 mmHg, DBP 80 < 90 mmHg) and hypertensive (SBP ≥ 140 mmHg, DBP ≥ 90 mmHg). All equipment were standardized and validated before the commencement of the study. The measuring indicator of the weighing machine was calibrated to zero before recording the data from each participant. Measurements were recorded in the morning between 8:00 and 11:00 a.m. In all cases for the three communities, BMI, SBP, and DBP were normally distributed. One-way analysis of variance (ANOVA) was used to study the ethnic differences of the parameters. Normality tests for residuals in ANOVA also has shown that data were within an acceptable range of normal distribution (Shapiro-Wilk W, p > .05, skewness and kurtosis). Frequency diagram, symmetry plots, and quantile plots of the residuals with respect to the communities also has shown normal distribution. Equal variances were assumed (by Bartlett’s Test) in three communities with respect to ANOVA at levels of BMI and BP (systolic and diastolic). Univariate general linear model (GLM) of BP (SBP and DBP) at levels of BMI-based nutritional status with age as covariate was studied for ethnic groups. The analyses constructed various tests to determine which factors (levels) had statistically significant effects on the response variable. It was tested for significance (in one-way ANOVA and ANCOVA or GLM) amongs levels of systolic and diastolic BP (normotensive, prehypertensive, and hypertensive) and levels of BMI (undernutrition, normal, and overweight). The F-tests in the ANOVA identified the significant factors. For each significant factor, the pairwise post hoc tests showed which means were significantly different from others. Tukey honestly significant difference HSD was considered in all cases of post hoc tests in three samples of men. Fisher’s LSD procedure was also checked simultaneously. Type III sums of squares had been chosen and the contribution of each factor was measured having removed the effects of other factors. The p values tested the statistical significance of each factor. Distribution of BMI at each level (normotensive, prehypertensive, and hypertensive) of BP has been studied. It also showed the standard error of the mean, which was a measure of its sampling variability. Columns showed 95.0% confidence intervals for each mean. Discriminant function analysis was done to understand how far ethnic background, SBP, and DBP as predictors could explain the different levels of nutritional status based on BMI (undernutrition, normal, or overweight). Moreover, to understand either SBP or DBP as discriminating variable or predictor had more of a contribution towards the discrimination of those groups (nutritional status). All statistical analyses were undertaken using the SPSS Statistical Package (Version 13.00) and Statgraphics Centurion XV.II. Statistical significance was set a priori at p < .05.
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Ethical approval (based on research projects sponsored by the University Grants Commission, New Delhi during 2008–2009 and Indian Council of Medical Research, New Delhi during 2009–2011) and prior permission was obtained from Vidyasagar University Ethics Committee and local community leaders, before commencement of the study. It may be mentioned herewith that the author was previously attached with the postgraduate Department of Anthropology of Vidyasagar University. Informed consent was obtained from the community leaders and also from each participant. Information on ethnicity, age, occupation, and educational status were obtained from all participants with the help of a pre-validated questionnaire. Confidentiality of personal information of the participants was maintained by the investigator.
RESULTS Samples showed mature men representing three ethnic groups. Mean age of the men (N = 242) was 42.84 years (± SD = 9.44). Mean height was 162.96 cm (SD = 5.71). Average body weight or BW (Range: 39 to 79 kg) of the adults was not high (Mean 55.18 kg, SD = 8.31) and mean BMI (Range 15.94 to 29.02 kg/m2 ) were observed to be normal (20. 74 kg/m2 , SD = 2.65). Mean SBP (130.29 mmHg, SD= 18.61), and DBP (82.90 mmHg, SD = 11.71) were also found to be within the normal range. The overall results indicated that the men in this region were not suffering from either undernutrition or hypertension. However, the scenario changed when studies were done for the communities separately. No significant age differences were observed with regard to the anthropometric (height, weight) and physiometric measurements (SBP, DBP) and BMI, when studied separately in three ethnic groups. However, the pooled sample (N = 242) showed significant age trends in BW (F = 17.61; p < .05) and BMI (F = 20.94; p < .05). Table 1 presented the descriptive statistics of variables in three communities under study along with variation measured by F values of ANOVA. Height and blood pressure (SBP and DBP) did not show significant variation between communities. However, age, BW, and BMI varied significantly. Adult Dhimals had lowest BW, and BMI and Mech adults showed the highest mean. Rajbanshi adults had intermediate mean values with respect to these two measures. The Mech community was represented by relatively younger adults (< 40 years), compared to other groups. The men in this study (N = 242) exhibited higher rates of undernutrition (19.80%) than overweight (9.10%). None was found to be obese. Prevalence of undernutrition was highest among Dhimal (30.68%) and lowest among Mech (8.45%). Rajbanshi males also had a remarkable rate of undernutrition
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TABLE 1 Descriptive Statistics of Variables with Ethnic Difference Tested by One-way ANOVA in Three Adult Male Populations at Naxalbari, Darjeeling Variables
Populations
Age (years)
Dhimal Mech Rajbanshi Dhimal Mech Rajbanshi Dhimal Mech Rajbanshi Dhimal Mech Rajbanshi Dhimal Mech Rajbanshi Dhimal Mech Rajbanshi
Height (HT) BW (kg)
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BMI (kg/m2 ) SBP (mmHg) DBP (mmHg)
Mean (SD) 43.94 38.97 44.98 163.06 163.77 162.15 52.25 59.54 54.56 19.62 22.15 20.72 131.00 130.00 129.78 81.76 82.41 84.53
(9.57) (8.44) (9.21) (5.91) (5.66) (5.49) (6.76) (8.60) (8.08) (2.06) (2.64) (2.65) (10.76) (11.76) (9.97) (11.26) (9.86) (10.47)
F (p) 9.32 (< .05) 1.59 (.21) 17.61 (< .05) 20.94 (< .05) 0.10 (.90) 1.29 (.28)
Note. SD: Standard Deviation; Dhimal, n = 88; Mech, n = 71; Rajbanshi, n = 83.
(18.07%). The rate of overweight was highest among Mech (19.72%), in comparison with either Rajbanshi (7.23) or Dhimal (2.27%). Rates of nutritional status in three communities varied significantly (Chi-square = 24.00, p < .0001) (figure 1). Table 2 shows systolic and diastolic blood pressures among normal, prehypertensive and hypertensive men. ANOVA showed significant differences of SBP and DBP by levels of respective BPs in three adult male samples along with the pooled sample (N = 242). A higher rate of hypertension (38.55%) with respect to DBP was observed among Rajbanshi men compared to other samples. The rate of SBP-based hypertension was highest among Dhimals (29.55%). Prevalence of pre-hypertension showed Mech men had much higher rates (56.34%) than did the two other groups (figure 2). No significant ethnic variation was observed (Chi-squared test) with respect to BP (SBP and DBP) in its three levels (i.e., normal, pre-hypertension, hypertension) or two (i.e., hypertension or not). Table 3 showed distributions of mean BMI and blood pressures (SBP and DBP) at levels of BMI cut-off values determining nutritional status (i.e., undernutrition, normal, and overweight). In univariate general linear model (after controlling age) significant difference of SBP at levels of BMI has been found among Rajbanshis. DBP showed significant difference at BMI levels among Dhimal males. Gradual rise of SBP and DBP was found with the rise of levels of BMI and nutritional status.
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FIGURE 1 Rates of nutritional status in three adult male populations at Naxalbari, Darjeeling. TABLE 2 Rates (%) and Mean of Blood Pressure Levels (mmHg) in Three Adult Male Populations at Naxalbari, Darjeeling SBP Communities
DBP
Levels of BP
%
Mean (SD)
Dhimal (n = 88)
Normal Prehypertensive Hypertensive ANOVA, F (p)
31.81 38.64 29.55
110.79 127.76 157.00 153.84
(6.19) (6.20) (15.24) (< .05)∗ a
43.18 28.41 28.41
71.84 83.16 95.44 140.62
(6.28) (3.41) (5.85) (< .05)∗ b
Mech (n = 71)
Normal Prehypertensive Hypertensive ANOVA, F (p)
22.53 56.34 21.13
111.88 130.00 149.33 154.85
(2.47) (5.20) (9.40) (< .05)∗ c
33.80 43.66 22.54
72.08 83.45 95.88 142.89
(4.31) (3.52) (5.82) (< .05)∗ d
Rajbanshi (n = 83)
Normal Prehypertensive Hypertensive ANOVA, F (p)
31.33 40.96 27.71
108.69 128.24 155.91 204.66
(6.01) (5.63) (12.42) (< .05)∗ e
34.94 26.51 38.55
70.55 82.55 98.56 171.19
(4.84) (3.28) (7.90) (< .05)∗ f
Total (N = 242)
Normal Prehypertensive Hypertensive ANOVA, F (p)
28.93 44.63 26.45
110.26 128.74 154.81 479.25
(5.57) (5.70) (13.24) (< .05)∗ g
37.60 32.23 30.17
71.49 83.10 96.90 453.66
(5.35) (3.39) (6.89) (< .05)∗ h
Note. SD and p values (ANOVA) are presented in parentheses. ∗ Post hoc tests are presented in Table 4.
%
Mean (SD)
263
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BMI and Blood Pressure in Men of Darjeeling
FIGURE 2 Prevalence (%) of blood pressure levels in three adult male populations of Darjeeling. TABLE 3 Variation of BMI and Blood Pressure at Different Levels of BMI in Three Adult Male Populations of Darjeeling BMI cut-off values Variables
Populations
Undernutrition Mean (SD)
Normal Mean (SD)
BMI
Dhimal Mech Rajbanshi Dhimal Mech Rajbanshi Dhimal Mech Rajbanshi
17.48 17.46 17.47 123.70 123.00 127.33 76.37 76.33 80.47
20.37 21.63 20.90 134.20 128.90 128.48 83.85 82.02 84.53
SBP DBP
∗
(0.62) (0.94) (0.83) (21.96) (9.01) (23.65) (11.52) (7.09) (14.40)
(1.35) (1.52) (1.60) (19.75) (13.65) (18.82) (10.37) (9.92) (12.86)
Overweight Mean (SD) 26.49 (1.23) 26.05 (0.90) 27.06 (1.46) 135.00 (15.55) 137.00 (14.86) 149.33 (12.50) 93.00 (7.07) 86.43 (9.52) 94.67 (14.29)
ANOVA F (p) 91.45 93.24 90.83 2.49 2.90 3.29 5.65 2.44 2.47
(< .05)∗ i (< .05)∗ j (< .05)∗ k (.09) (.06) (< .05)∗ l (< .05)∗ m (.09) (.09)
Post hoc tests are presented in Table 4.
Table 4 presented the post hoc test of the cases of significant differences observed tested by ANOVA for types of BP and BMI in table 2 and table 3. These tests exhibited significant differences of BP or BMI between each pairs of normotensive, prehypertensive and hypertensive sections of three adult male samples. Moreover, post hoc tests showed significant differences of BMI or BP at paired levels of undernutrition, normal and overweight except two cases among Dhimal males. Diastolic blood pressure in relation with levels between overweight versus normal or overweight
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TABLE 4 Post Hoc Test (Tukey HSD) for Cases with Significant Difference in Test of ANOVA presented in Tables 2 and 3
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Samples and interactions
Level 1
Level 2
Mean difference (Level 1–Level 2)
Std. error
p
Dhimal: SBP at SBP levels∗ a
Normotensive Prehypertensive Normotensive Hypertensive Prehypertensive Hypertensive
−16.98 −46.21 −29.24
2.49 2.66 2.55
Ecology of Food and Nutrition Publication details, including instructions for authors and subscription information: http://www.tandfonline.com/loi/gefn20
Body Mass Index and Blood Pressure among Men of Three Ethnic Groups of Darjeeling, West Bengal, India a
Sudip Datta Banik a
Department of Human Ecology, Cinvestav-IPN, Unidad Mérida, Yucatan, Mexico Published online: 15 Apr 2014.
To cite this article: Sudip Datta Banik (2014) Body Mass Index and Blood Pressure among Men of Three Ethnic Groups of Darjeeling, West Bengal, India, Ecology of Food and Nutrition, 53:3, 256-272, DOI: 10.1080/03670244.2013.814462 To link to this article: http://dx.doi.org/10.1080/03670244.2013.814462
PLEASE SCROLL DOWN FOR ARTICLE Taylor & Francis makes every effort to ensure the accuracy of all the information (the “Content”) contained in the publications on our platform. However, Taylor & Francis, our agents, and our licensors make no representations or warranties whatsoever as to the accuracy, completeness, or suitability for any purpose of the Content. Any opinions and views expressed in this publication are the opinions and views of the authors, and are not the views of or endorsed by Taylor & Francis. The accuracy of the Content should not be relied upon and should be independently verified with primary sources of information. Taylor and Francis shall not be liable for any losses, actions, claims, proceedings, demands, costs, expenses, damages, and other liabilities whatsoever or howsoever caused arising directly or indirectly in connection with, in relation to or arising out of the use of the Content. This article may be used for research, teaching, and private study purposes. Any substantial or systematic reproduction, redistribution, reselling, loan, sub-licensing, systematic supply, or distribution in any form to anyone is expressly forbidden. Terms & Conditions of access and use can be found at http://www.tandfonline.com/page/termsand-conditions
Ecology of Food and Nutrition, 53:256–272, 2014 Copyright © Taylor & Francis Group, LLC ISSN: 0367-0244 print/1543-5237 online DOI: 10.1080/03670244.2013.814462
Body Mass Index and Blood Pressure among Men of Three Ethnic Groups of Darjeeling, West Bengal, India SUDIP DATTA BANIK Downloaded by [University of South Florida] at 10:09 14 October 2014
Department of Human Ecology, Cinvestav-IPN, Unidad Mérida, Yucatan, Mexico
This study was undertaken from 2009–2011 to understand the association between body mass index (BMI) and blood pressure (BP) (systolic or SBP and diastolic or DBP) among randomly chosen men, aged 30 to 59 years, of three endogamous communities in Darjeeling, West Bengal, India: Dhimal (n = 88), Mech (n = 71), and Rajbanshi (n = 83). Analysis of variance was applied. Remarkable rates of BMI-based undernutrition (chronic energy deficiency or CED) were recorded among Dhimals (31%) and Rajbanshis (18%). Notable prevalence of overweight (20%) was recorded among men of Mech community. None were found to be obese in three samples. Mean SBP and DBP were found to rise consistently at levels of BMI (undernutrition, normal, and overweight). BMI was observed to rise consistently at levels of blood pressures (normotensive, prehypertensive, and hypertensive). Among Mech, this pattern was found to be more conspicuous. DBP was found to be more sensitive with changes of BMI in men. KEYWORDS hypertension, normal, overweight, undernutrition
Blood pressure (BP) is an important physiological factor, sensitive to socioeconomic conditions, urbanization, activity patterns, diet, body weight and fat, and other physical and cultural determinants in addition to its genetic predisposition, familial association, and ethnic background (Kearney et al. 2004; WHO 1996). BP is one of the important indicators of several cardiovascular complications (Canoy et al. 2004). Nutritional status is an important factor Address correspondence to Dr. Sudip Datta Banik, Department of Human Ecology, Cinvestav–IPN, Unidad Mérida, Antigua Carretera a Progreso km 6., Mérida 97310, Yucatán, Mexico. E-mail: [email protected] 256
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that determines blood pressure. In epidemiological research, understanding the relationship between body mass index (BMI) and BP is important. A positive correlation between BMI and BP had been reported from adult Caucasian populations (Tesfaye et al. 2007). BMI had been observed to be related with BP among adults in Sweden (Henriksson et al. 2003), China (Zhou 2002), Pakistan (Khan et al. 2008), and India (Das, Sanyal, and Basu 2005; Desmukh et al. 2006; Gopi Chand and Rao 2007; Gupta 2004; Gupta et al. 2007; Kusuma, Babu, and Naidu 2004; Reddy, Reddy, and Sudha 2010; Santhirani et al. 2003). In West Bengal, India, especially in urban and semi-urban societies, increased BP was a major health concern for adults (Chakraborty, Bose, and Bisai 2009; Datta Banik 2007; Ghosh and Bandyopadhyay 2007). The risk of hypertension was relatively lower in adults who had normal BMI (< 24 kg/m2 ) in comparison with overweight individuals in Uzbekistan (Mishra 2005). In developing countries, a higher risk of cardiovascular mortality among lean individuals had been documented (Goldbourt et al. 1987; Stamler et al. 1991; cf. Tesfaye et al. 2007). A high rate of undernutrition was found among men in Ethiopia (36.7%), Vietnam (32.5%), and Indonesia (14%). In that study, the prevalence of hypertension was found to be higher in first and fifth quintiles of BMI that suggested higher cardiovascular risk in individuals who were suffering from either undernutrition or overweight (Tesfaye et al. 2007). In some adult tribal populations of India, morbidity increased in males due to the co-existence of high rates of underweight (45.3%) and hypertension (systolic BP 15.2%, diastolic BP 25.5%) (Kapoor et al. 2012). High BMI, low physical activity, non-vegetarian diet, and consumption of alcohol and tobacco were associated risk factors for increasing rate of hypertension in adults of North India (Gupta et al. 2012). Similar reports from rural and tribal populations, on BP in relation to nutritional status, especially from Darjeeling District of West Bengal, India were not available. Moreover, data from endogamous communities of Darjeeling, like Dhimal, Mech, and Rajbanshi, were very few (Datta Banik 2011; Datta Banik et al. 2007; Datta Banik, Basu et al. 2008a; Datta Banik, Jana et al. 2008b; Datta Banik, Bhattacharjee, et al. 2009b). The principal objective of this study was to investigate the relationship between BMI-based nutritional status and BP (systolic and diastolic) among men of Dhimal, Mech, and Rajbanshi communities at Naxalbari in Darjeeling district of the state of West Bengal in India.
MATERIALS AND METHODS Dhimals were found in hamlets called “Dhimal basti” or “Dera”: Ketugaburjot and Siuborjot. Mech hamlets were Nehaljot (Tarabari) and South Kotiajot. Rajbanshis were found in hamlets namely Ketugaburjot and Kumarsinghjot.
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These villages at Naxalbari were located around 35 km from Siliguri town in Darjeeling District, which is approximately 580 km towards the north from Kolkata (Calcutta), the provincial capital of West Bengal. The samples were free from any selection bias. Participants were not chosen on the basis of bodily structure and proportion. The sample included apparently healthy men (age range between 30 and 59 years) of three communities (Dhimal, Mech, and Rajbanshi). The survey was carried out between July 2009 and November 2011 in the villages at Naxalbari block and Maniram Panchayat in Darjeeling district. Block and Panchayat were statutory bodies of the Government. Censuses of those populations at Naxalbari were recorded through household survey. Randomly selected individuals constituting the sizes of three samples (Dhimal = 88, Mech = 71, Rajbanshi = 83) exhibited similar proportionate representations of the respective populations at Naxalbari with respect to the studied age groups. Dhimal, Mech, and Rajbanshi represented 36.4%, 29.3%, and 34.3% of the total individuals (N = 242) in the study, respectively. The sample (N = 242) covered almost 85% of the total number of men (aged 30 to 59 years) in 10 hamlets of these three communities at Naxalbari. Numbers of participants in age-groups, representing three ethnic groups, were: 30–39 years (Dhimal = 32, Mech = 32, Rajbanshi = 21); 40–49 years (Dhimal = 30, Mech = 28, Rajbanshi = 33); 50–59 years (Dhimal = 26, Mech = 11, Rajbanshi = 29). Anthropometric and physiometric data were collected from the participants who reported not to be suffering from any chronic or acute diseases three months before the survey. None of the participants suffered from malaria, which was very common and highly prevalent in that region. Only those individuals who were suffering from any acute or chronic diseases (e.g., malaria, tuberculosis, hepatitis, cough and cold with fever, skin infections) and had physical handicaps or remained absent during the survey, could not be included in the study; eight individuals were excluded based on such criteria. All anthropometric measurements of lightly-clothed participants were taken by the author, using standard anthropometric techniques (Lohman, Roche, and Martorell 1988). Height (HT in centimeter) and body weight (BW in kilogram) were taken to the nearest 0.1 cm and 0.5 kg, respectively, using standard Martin’s anthropometer and weighing scale (Doctor Beliram and Sons, New Delhi, India). BMI was computed as body weight (kg) divided by squared height (meter) (WHO 1995). Cut-off values of BMI for adults (WHO 1995) determining levels of nutritional status were: undernutrition (< 18.45 Kg/m2 ), normal (18.50 - 24.99 Kg/m2 ) and overweight (> 25.00 Kg/m2 ). BMI cut-off values for Asian people, recommended by the WHO expert consultation (WHO 2004), displayed similar distributions in the present data. Physiometric measurements of systolic (SBP) and diastolic (DBP) blood pressures (mmHg) were measured by standard mercury sphygmomanometer (Diamond, New Delhi) following standard
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protocol (Pickering et al. 2005). Based on blood pressure, participants were classified as normal (SBP ≤ 120 mmHg, DBP ≤ 80 mmHg), prehypertensive (SBP 120 < 140 mmHg, DBP 80 < 90 mmHg) and hypertensive (SBP ≥ 140 mmHg, DBP ≥ 90 mmHg). All equipment were standardized and validated before the commencement of the study. The measuring indicator of the weighing machine was calibrated to zero before recording the data from each participant. Measurements were recorded in the morning between 8:00 and 11:00 a.m. In all cases for the three communities, BMI, SBP, and DBP were normally distributed. One-way analysis of variance (ANOVA) was used to study the ethnic differences of the parameters. Normality tests for residuals in ANOVA also has shown that data were within an acceptable range of normal distribution (Shapiro-Wilk W, p > .05, skewness and kurtosis). Frequency diagram, symmetry plots, and quantile plots of the residuals with respect to the communities also has shown normal distribution. Equal variances were assumed (by Bartlett’s Test) in three communities with respect to ANOVA at levels of BMI and BP (systolic and diastolic). Univariate general linear model (GLM) of BP (SBP and DBP) at levels of BMI-based nutritional status with age as covariate was studied for ethnic groups. The analyses constructed various tests to determine which factors (levels) had statistically significant effects on the response variable. It was tested for significance (in one-way ANOVA and ANCOVA or GLM) amongs levels of systolic and diastolic BP (normotensive, prehypertensive, and hypertensive) and levels of BMI (undernutrition, normal, and overweight). The F-tests in the ANOVA identified the significant factors. For each significant factor, the pairwise post hoc tests showed which means were significantly different from others. Tukey honestly significant difference HSD was considered in all cases of post hoc tests in three samples of men. Fisher’s LSD procedure was also checked simultaneously. Type III sums of squares had been chosen and the contribution of each factor was measured having removed the effects of other factors. The p values tested the statistical significance of each factor. Distribution of BMI at each level (normotensive, prehypertensive, and hypertensive) of BP has been studied. It also showed the standard error of the mean, which was a measure of its sampling variability. Columns showed 95.0% confidence intervals for each mean. Discriminant function analysis was done to understand how far ethnic background, SBP, and DBP as predictors could explain the different levels of nutritional status based on BMI (undernutrition, normal, or overweight). Moreover, to understand either SBP or DBP as discriminating variable or predictor had more of a contribution towards the discrimination of those groups (nutritional status). All statistical analyses were undertaken using the SPSS Statistical Package (Version 13.00) and Statgraphics Centurion XV.II. Statistical significance was set a priori at p < .05.
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Ethical approval (based on research projects sponsored by the University Grants Commission, New Delhi during 2008–2009 and Indian Council of Medical Research, New Delhi during 2009–2011) and prior permission was obtained from Vidyasagar University Ethics Committee and local community leaders, before commencement of the study. It may be mentioned herewith that the author was previously attached with the postgraduate Department of Anthropology of Vidyasagar University. Informed consent was obtained from the community leaders and also from each participant. Information on ethnicity, age, occupation, and educational status were obtained from all participants with the help of a pre-validated questionnaire. Confidentiality of personal information of the participants was maintained by the investigator.
RESULTS Samples showed mature men representing three ethnic groups. Mean age of the men (N = 242) was 42.84 years (± SD = 9.44). Mean height was 162.96 cm (SD = 5.71). Average body weight or BW (Range: 39 to 79 kg) of the adults was not high (Mean 55.18 kg, SD = 8.31) and mean BMI (Range 15.94 to 29.02 kg/m2 ) were observed to be normal (20. 74 kg/m2 , SD = 2.65). Mean SBP (130.29 mmHg, SD= 18.61), and DBP (82.90 mmHg, SD = 11.71) were also found to be within the normal range. The overall results indicated that the men in this region were not suffering from either undernutrition or hypertension. However, the scenario changed when studies were done for the communities separately. No significant age differences were observed with regard to the anthropometric (height, weight) and physiometric measurements (SBP, DBP) and BMI, when studied separately in three ethnic groups. However, the pooled sample (N = 242) showed significant age trends in BW (F = 17.61; p < .05) and BMI (F = 20.94; p < .05). Table 1 presented the descriptive statistics of variables in three communities under study along with variation measured by F values of ANOVA. Height and blood pressure (SBP and DBP) did not show significant variation between communities. However, age, BW, and BMI varied significantly. Adult Dhimals had lowest BW, and BMI and Mech adults showed the highest mean. Rajbanshi adults had intermediate mean values with respect to these two measures. The Mech community was represented by relatively younger adults (< 40 years), compared to other groups. The men in this study (N = 242) exhibited higher rates of undernutrition (19.80%) than overweight (9.10%). None was found to be obese. Prevalence of undernutrition was highest among Dhimal (30.68%) and lowest among Mech (8.45%). Rajbanshi males also had a remarkable rate of undernutrition
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TABLE 1 Descriptive Statistics of Variables with Ethnic Difference Tested by One-way ANOVA in Three Adult Male Populations at Naxalbari, Darjeeling Variables
Populations
Age (years)
Dhimal Mech Rajbanshi Dhimal Mech Rajbanshi Dhimal Mech Rajbanshi Dhimal Mech Rajbanshi Dhimal Mech Rajbanshi Dhimal Mech Rajbanshi
Height (HT) BW (kg)
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BMI (kg/m2 ) SBP (mmHg) DBP (mmHg)
Mean (SD) 43.94 38.97 44.98 163.06 163.77 162.15 52.25 59.54 54.56 19.62 22.15 20.72 131.00 130.00 129.78 81.76 82.41 84.53
(9.57) (8.44) (9.21) (5.91) (5.66) (5.49) (6.76) (8.60) (8.08) (2.06) (2.64) (2.65) (10.76) (11.76) (9.97) (11.26) (9.86) (10.47)
F (p) 9.32 (< .05) 1.59 (.21) 17.61 (< .05) 20.94 (< .05) 0.10 (.90) 1.29 (.28)
Note. SD: Standard Deviation; Dhimal, n = 88; Mech, n = 71; Rajbanshi, n = 83.
(18.07%). The rate of overweight was highest among Mech (19.72%), in comparison with either Rajbanshi (7.23) or Dhimal (2.27%). Rates of nutritional status in three communities varied significantly (Chi-square = 24.00, p < .0001) (figure 1). Table 2 shows systolic and diastolic blood pressures among normal, prehypertensive and hypertensive men. ANOVA showed significant differences of SBP and DBP by levels of respective BPs in three adult male samples along with the pooled sample (N = 242). A higher rate of hypertension (38.55%) with respect to DBP was observed among Rajbanshi men compared to other samples. The rate of SBP-based hypertension was highest among Dhimals (29.55%). Prevalence of pre-hypertension showed Mech men had much higher rates (56.34%) than did the two other groups (figure 2). No significant ethnic variation was observed (Chi-squared test) with respect to BP (SBP and DBP) in its three levels (i.e., normal, pre-hypertension, hypertension) or two (i.e., hypertension or not). Table 3 showed distributions of mean BMI and blood pressures (SBP and DBP) at levels of BMI cut-off values determining nutritional status (i.e., undernutrition, normal, and overweight). In univariate general linear model (after controlling age) significant difference of SBP at levels of BMI has been found among Rajbanshis. DBP showed significant difference at BMI levels among Dhimal males. Gradual rise of SBP and DBP was found with the rise of levels of BMI and nutritional status.
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FIGURE 1 Rates of nutritional status in three adult male populations at Naxalbari, Darjeeling. TABLE 2 Rates (%) and Mean of Blood Pressure Levels (mmHg) in Three Adult Male Populations at Naxalbari, Darjeeling SBP Communities
DBP
Levels of BP
%
Mean (SD)
Dhimal (n = 88)
Normal Prehypertensive Hypertensive ANOVA, F (p)
31.81 38.64 29.55
110.79 127.76 157.00 153.84
(6.19) (6.20) (15.24) (< .05)∗ a
43.18 28.41 28.41
71.84 83.16 95.44 140.62
(6.28) (3.41) (5.85) (< .05)∗ b
Mech (n = 71)
Normal Prehypertensive Hypertensive ANOVA, F (p)
22.53 56.34 21.13
111.88 130.00 149.33 154.85
(2.47) (5.20) (9.40) (< .05)∗ c
33.80 43.66 22.54
72.08 83.45 95.88 142.89
(4.31) (3.52) (5.82) (< .05)∗ d
Rajbanshi (n = 83)
Normal Prehypertensive Hypertensive ANOVA, F (p)
31.33 40.96 27.71
108.69 128.24 155.91 204.66
(6.01) (5.63) (12.42) (< .05)∗ e
34.94 26.51 38.55
70.55 82.55 98.56 171.19
(4.84) (3.28) (7.90) (< .05)∗ f
Total (N = 242)
Normal Prehypertensive Hypertensive ANOVA, F (p)
28.93 44.63 26.45
110.26 128.74 154.81 479.25
(5.57) (5.70) (13.24) (< .05)∗ g
37.60 32.23 30.17
71.49 83.10 96.90 453.66
(5.35) (3.39) (6.89) (< .05)∗ h
Note. SD and p values (ANOVA) are presented in parentheses. ∗ Post hoc tests are presented in Table 4.
%
Mean (SD)
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FIGURE 2 Prevalence (%) of blood pressure levels in three adult male populations of Darjeeling. TABLE 3 Variation of BMI and Blood Pressure at Different Levels of BMI in Three Adult Male Populations of Darjeeling BMI cut-off values Variables
Populations
Undernutrition Mean (SD)
Normal Mean (SD)
BMI
Dhimal Mech Rajbanshi Dhimal Mech Rajbanshi Dhimal Mech Rajbanshi
17.48 17.46 17.47 123.70 123.00 127.33 76.37 76.33 80.47
20.37 21.63 20.90 134.20 128.90 128.48 83.85 82.02 84.53
SBP DBP
∗
(0.62) (0.94) (0.83) (21.96) (9.01) (23.65) (11.52) (7.09) (14.40)
(1.35) (1.52) (1.60) (19.75) (13.65) (18.82) (10.37) (9.92) (12.86)
Overweight Mean (SD) 26.49 (1.23) 26.05 (0.90) 27.06 (1.46) 135.00 (15.55) 137.00 (14.86) 149.33 (12.50) 93.00 (7.07) 86.43 (9.52) 94.67 (14.29)
ANOVA F (p) 91.45 93.24 90.83 2.49 2.90 3.29 5.65 2.44 2.47
(< .05)∗ i (< .05)∗ j (< .05)∗ k (.09) (.06) (< .05)∗ l (< .05)∗ m (.09) (.09)
Post hoc tests are presented in Table 4.
Table 4 presented the post hoc test of the cases of significant differences observed tested by ANOVA for types of BP and BMI in table 2 and table 3. These tests exhibited significant differences of BP or BMI between each pairs of normotensive, prehypertensive and hypertensive sections of three adult male samples. Moreover, post hoc tests showed significant differences of BMI or BP at paired levels of undernutrition, normal and overweight except two cases among Dhimal males. Diastolic blood pressure in relation with levels between overweight versus normal or overweight
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TABLE 4 Post Hoc Test (Tukey HSD) for Cases with Significant Difference in Test of ANOVA presented in Tables 2 and 3
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Samples and interactions
Level 1
Level 2
Mean difference (Level 1–Level 2)
Std. error
p
Dhimal: SBP at SBP levels∗ a
Normotensive Prehypertensive Normotensive Hypertensive Prehypertensive Hypertensive
−16.98 −46.21 −29.24
2.49 2.66 2.55
