O r i g i n a l A r t i c l e
Association of betel nut chewing with chronic kidney disease:
A retrospective 7-year study in Taiwan
nep_1489751..757YUEH-HAN HSU,
1,4WEN-HSIN LIU,
2WEI CHEN,
3,5YI-CHUN KUO,
1CHIH-YEN HSIAO,
1PEIR-HAUR HUNG,
1ING-CHING JONG,
1PEI-CHUN CHIANG
1and CHIH-CHENG HSU
6,71Division of Nephrology, Department of Internal Medicine, Chia-Yi Christian Hospital,2Division of Family Medicine, Chia-Yi Christian Hospital,3Division of Pulmonary and Critical Care Medicine, Department of Internal Medicine, Chia-Yi Christian Hospital, Chia-Yi,4Department of Nursing, Min-Hwei College of Health Care Management, Tainan,5Department of Respiratory Therapy, China Medical University,6Department of Health Services Administration, China Medical University and Hospital, Taichung, and7Institute of Population Health Sciences, National Health Research Institutes, Zhunan, Taiwan
KEY WORDS:
betel nut, chronic kidney disease.
Correspondence:
Dr Chih-Cheng Hsu, Institute of Population Health Sciences, National Health Research Institutes, Zhunan, Taiwan, 35 Keyan Road, Zhunan, Miaoli County 35053, Taiwan. Email: [email protected]
Accepted for publication 19 June 2011. Accepted manuscript online 7 July 2011. doi:10.1111/j.1440-1797.2011.01489.x Conflicts of Interest: None to disclose.
SUMMARY AT A GLANCE
This paper details a population-based study in Taiwan aimed at determining a possible association between Betel nut chewing and chronic kidney disease. Much larger than previous studies in the area, the authors have determined that an association exists in some subgroups of their large cohort.
ABSTRACT:
Aim:
Only few studies have reported that betel nut (BN) chewing is
inde-pendently associated with chronic kidney disease (CKD); however, the
sample size was relatively small. This study was to explore further the
association between BN chewing and CKD using a larger case series.
Methods:
We retrospectively reviewed the records of a health check-up
program from 2003 to 2009. Laboratory tests, medical history and status of
cigarette smoking, alcohol drinking and BN chewing were compared
between CKD and non-CKD groups. We checked interaction effects between
BN chewing and all other covariates, and conducted multivariate logistic
regression analysis to explore the risk of CKD with BN chewing.
Results:
A total of 27 482 participants (15 491 females and 11 991 males,
mean age 58.02
1 11.85 years) were included in the study, of whom 4519
(16.4%) had CKD and 1608 (5.9%) chewed BN. CKD prevalence in the
chewers was higher than in the non-chewers in all age groups per decade.
BN chewing was significantly associated with CKD in overall subjects (odds
ratio (OR)
= 1.23, P = 0.027) and also in the male (OR = 1.23, P = 0.035),
non-drinking (OR
= 1.62, P = 0.000), diabetic (OR = 1.27, P = 0.021), and
non-proteinuric groups (OR
= 1.30, P = 0.013). This relationship was insignificant
in female, drinking, diabetic and proteinuric groups.
Conclusion:
The association between BN chewing and CKD seemed
condi-tional on demographics, health behaviours, and underlying co-morbidities.
This association should be interpreted cautiously.
INTRODUCTION
The incidence of end-stage renal disease (ESRD) has
increased rapidly worldwide.
1Taiwan has the highest ESRD
incidence and prevalence in the world,
2leading to heavy
burdens on health care resources and national finance. Early
detection of potential risk factors and early treatment of
chronic kidney disease (CKD) may slow the decline of renal
function and prevent the development of severe
cardiovas-cular complications.
3In addition to well-established CKD
risk factors, such as age, hypertension, diabetes, obesity
and metabolic syndrome, there are still other potentially
modifiable risk factors to be identified for the prevention and
management of CKD.
Betel nut (BN) is the fourth most widely used addictive
substance in the world, and BN chewers make up over 10%
of the world’s population.
4The prevalence of BN use has
increased gradually in Taiwan, especially in rural areas.
5In
addition to the associations with oral cancer,
6cardiovascular
disorders,
7hyperglycemia,
8,9obesity,
10metabolic syndrome,
8type 2 diabetes mellitus,
9liver cirrhosis
11and increase in
urinary albumin excretion,
12BN chewing has also been
reported to be associated with CKD.
13,14However, the
was relatively small (n
= 677) and the adjustment factors
included were limited. In the present study, we conducted a
retrospective analysis with the currently largest available
series (27 482 participants, 4519 CKD) to explore the
in-depth relationship between BN chewing and CKD in
Taiwan.
METHODS
Participants
From 2003 to 2009, a total of 34 372 people attended a national health insurance health check-up program (NHI-CP) in Chia-Yi Christian Hospital, with 36 577 records in total; 1481 people attended the program more than once in different years with a total of 2205 extra visits. All of the participants were enrolled in this retrospective record-review study. For those receiving more than one health check-up, only the first was included. Participants with incomplete data (n= 6890) were excluded from the analysis, and a total of 27 482 participants were included. The study was approved by the Institutional Review Board of this hospital.
Methods
The NHI-CP is a formally designed physical check-up package for adults at or over the age of 40, issued by the Bureau of National Health Insurance (BNHI), Taiwan. It contains a standard lab test package, a brief questionnaire for basic demographic data (age, sex, address), health behaviours (status of cigarette smoking, alcohol drinking and BN chewing), personal medical history (including diabetes, hypertension, and hyperlipidemia), and a physical ex-amination (PE). The participants were asked to report three aforementioned health behaviours in the last 6 months as a non-user, social user or regular user. PE data include body height, body weight, systolic blood pressure (SBP), and diastolic blood pressure (DBP), and body mass index (BMI) was derived from the PE data. The standard laboratory studies include serum creatinine (Scr), total cholesterol (TC), triglycerides (TG), uric acid (UA), fasting blood sugar (FBS), alanine aminotransferase (ALT), hemoglobin (Hb) and urinalysis (including bio-chemical and sediment microscopic exams), which were all measured with standard automated technol-ogy. In addition, we also calculated estimated glomerular filtration rates (eGFR) for all included participants using the Modification of Diet in Renal Disease (MDRD) formula.3Participants fasted for 12 h overnight before blood sampling in the morning.
Variable definition
Chronic kidney disease was defined as an eGFR less than 60 mL/min per 1.73 m2as calculated by the MDRD formula, and then further stratified into CKD stage 3, 4 and 5 if the eGFR was 30–59 mL/min per 1.73 m2, 15–29 mL/min per 1.73 m2 and <15 mL/min per 1.73 m2, respectively.3Hypertension (HTN) was defined as having a past personal history (regardless of whether or not they were taking medications), or a blood pressure of at least 140/90 mmHg.15 Diabe-tes mellitus (DM) was defined as a fasting plasma glucose level of 126 mg/dL or higher, or a history of DM with or without medica-tion.16Hyperlipidemia was defined as having a serum total
choles-terol level of 200 mg/dL or higher, or a triglyceride level of 200 mg/dL or higher, or a past personal history of high TC or TG with or without medication.17 Participants were defined as non-smokers if they did not smoke and as non-smokers if they smoked socially or regularly regardless of the amount they smoked. Participants were defined as non-chewers if they did not consume any BN at all; as chewers if they consumed BN socially or regularly. Likewise, partici-pants were defined as non-drinkers if they did not consume any alcohol and as drinkers if they consumed alcohol socially or regu-larly. Proteinuria was defined as having +/- or heavier protein response (including+ to 4+) in a urine dipstick test. Liver dysfunc-tion was defined as an ALT level>44 IU/L according to the upper limits of the automated technology in this hospital, and anaemia was defined as an Hb level<13 g/dL in males, and <12 g/dL in females.18 Hyperuricemia was defined as a serum UA level>7.0 mg/dL accord-ing to domestic guidelines.19
Laboratory methodology
Biochemistry tests including ALT, TC, TG, UA, and Scr were mea-sured by an automatic analyzer (Hitachi 7170, Hitachi High Tech-nologies Co, Tokyo, Japan). The test reagent for ALT was manufactured by Roche Diagnostics GmbH, Germany, and the reagents for all other biochemical tests were manufactured by Wako Pure Chemical Industries, Ltd, Japan. Hb analysis was measured by an automatic analyzer (Sysmex XE-2100/5000, Sysmex Co., Japan), and dipstick urinalysis was performed by an automated chemical analyzer (URISYS 2400, Roche Diagnostics, Germany).
Statistical analysis
Data were presented in a case-control manner, according to the status of being with and without CKD, and were reported as means and standard deviations or numbers and percentages as appropriate. Demographics, clinical characteristics and co-morbidities were ana-lyzed by the Student’s t-test or the Mann–Whitney U-test (as appro-priate) for continuous variables, and by thec2test for categorical variables.
Since age is significantly related to the decline of eGFR, we assessed the CKD prevalence of chewers versus non-chewers in different age groups (per decade until 70 years or older). The differ-ences of CKD prevalence were compared by thec2test.
To determine the association between BN chewing and CKD, we performed a multivariate logistic regression analysis (MLRA), choos-ing adjustment factors based on the followchoos-ing rationales: (i) factors that might influence CKD development, either contributing to or protecting from; (ii) potential confounding factors for CKD; and (iii) factors being both contributing factors and results of CKD. The chosen covariates included age, gender, BMI, drinking, smoking, HTN, DM, hyperlipidemia, hyperuricemia, anaemia, and proteinuria.
To test whether interaction effects (IE) existed among BN chewing and other variables, we conducted IE analyses between BN chewing and all other covariates selected for MLRA. We created a dummy variable as (BN¥ variable) and conducted separate multivariable regression analyses to test individual IE. For the covariates with significant IE, the odds ratios (OR) of CKD development related to BN chewing were estimated separately according to the statuses of these covariates.
All analyses were carried out using the SPSS for Windows statis-tical software package version 18 (SPSS Inc., Chicago, IL, USA).
P-values< 0.05 were considered to be statistically significant.
RESULTS
In total, 27 482 participants (15 491 females, 11 991 males,
mean age 58.02
1 11.85 years) were included in the analysis.
Of all participants, 4519 (16.4%) had CKD and 1608 (5.9%)
chewed BN. The prevalence of CKD in the BN chewers was
12.4%, and 16.7% in the non-chewers. The proportions of
chewers in CKD stage 3, 4, and 5 were 4.5%, 3.7% and
1.7%, respectively. Of the participants with CKD, 4.4%
chewed BN, and in the non-CKD participants, 6.1% chewed
BN (P
< 0.001).
As seen in Table 1, those who were found to have CKD
tended to be older, with a higher proportion of males, higher
BMI, higher SBP and DBP, higher Scr, TC, TG, UA, and FBS,
but lower eGFR, ALT and Hb levels. In the analysis of health
behaviours and co-morbidities, those who were found to
have CKD tended to have a higher prevalence of DM, HTN,
hyperlipidemia, proteinuria, anaemia and hyperuricemia,
but a lower proportion of BN chewing, smoking, drinking
and liver dysfunction (Table 2).
The analysis of CKD prevalence of those who chewed BN
versus non-chewers in the different age groups revealed that
in all age groups, BN chewers had a higher CKD prevalence,
although all P-values were
>0.05 in the comparisons
(Table 3).
In the MLRA models, the adjusted OR of CKD for BN
use was 1.23 (95% confidence interval (CI) 1.02–1.48,
P
= 0.027) (Table 4). IE analysis revealed that significant IE
were present among BN chewing, gender, drinking, DM and
proteinuria. For these four covariates, we conducted eight
further MLRA stratified by the level of each interacting
factor. When stratified by gender, the adjusted OR of CKD for
male BN users was 1.23 (95% CI 1.02–1.48, P
= 0.035)
(Table 5). When stratified by drinking status, the adjusted OR
of CKD for non-drinking BN users was 1.62 (95% CI 1.26–
Table 1 Characteristics of age, sex, blood pressure and laboratory profiles of the 27 482 participants stratified by chronic kidney disease (CKD) status
Overall subjects (n= 27 482) CKD(-) (n = 22 963, 83.6%) CKD(+) (n = 4519, 16.4%) Age (years) 58.021 11.85 56.001 11.80 68.321 10.19*** Male gender 11991 (43.6%) 9826 (42.8%) 2165 (47.9%)*** eGFR (mL/min/1.73 m2) 76.331 17.75 81.511 13.95 50.011 9.93*** BMI (kg/m2) 25.011 4.15 24.971 4.24 25.221 3.62*** Systolic BP (mmHg) 131.661 20.63 130.001 19.86 140.111 22.37*** Diastolic BP (mmHg) 76.951 12.23 76.691 12.03 78.271 13.16*** Creatinine (mg/dL) 0.981 0.37 0.901 0.18 1.411 0.69*** Cholesterol (mg/dL) 210.691 41.41 210.201 40.58 213.211 45.33*** Triglyceride (mg/dL) 139.431 132.25 137.001 133.48 151.781 125.10*** Uric acid (mg/dL) 6.031 1.68 5.811 1.53 7.171 1.91***
Fasting blood glucose (mg/dL) 104.671 38.10 103.721 36.57 109.461 44.77***
ALT (IU/L) 32.451 40.60 32.721 41.48 31.051 35.77*
Hemoglobin (g/dL) 14.141 1.67 14.201 1.63 13.791 1.80***
*P-value< 0.05; **P-value < 0.01; ***P-value < 0.001. Results are expressed as n (%) or means 1 standard deviation (SD). The conversion factors from Conventional Units to Standard International (S.I.) Units were: creatinine 88.4; cholesterol, 0.026; triglyceride, 0.01129; uric acid, 59.48; fasting sugar, 0.056; alanine aminotrans-ferase, 1.0; hemoglobin, 10. ALT, alanine aminotransferase; BMI, body mass index; BP, blood pressure; CKD, chronic kidney disease; eGFR, estimated glomerular filtration rate.
Table 2 Personal behaviours and co-morbidities of the 27 482 participants
stratified by chronic kidney disease (CKD) status Overall subjects (n= 27 482) CKD(–) (n= 22 963) CKD(+) (n= 4519) Smoker 6921 (25.2%) 5850 (25.5%) 1071 (23.7%)* Drinker 4594 (16.7%) 4096 (17.8%) 498 (11.0%)*** Betel nut chewer 1608 (5.9%) 1408 (6.1%) 200 (4.4%)*** Diabetes 3640 (13.2%) 2741 (11.9%) 899 (19.9%)*** Hypertension 11727 (42.7%) 8800 (38.3%) 2927 (64.8%)*** Hyperlipidemia 989 (3.6%) 746 (3.2%) 243 (5.4%)*** Proteinuria 2808 (10.2%) 1732 (7.5%) 1076 (23.8%)*** Liver dysfunction 4391 (16.0%) 3751 (16.3%) 640 (14.2%)*** Anemia 2592 (9.47%) 1816 (7.9%) 776 (17.2%)*** Hyperuricemia 6713 (24.4%) 4519 (19.7%) 2194 (48.6%)*** *P-value< 0.05; **P-value < 0.01; ***P-value < 0.001. Results are expressed as n (%). Definitions: Chewer: participants who chewed betel nut socially or regularly in the previous 6 months by self-reporting; CKD, eGFR< 60 mL/min/ 1.73 m2calculated by the Modification of Diet in Renal Disease formula; Smoker: participants who smoked socially, occasionally or regularly regard-less of the amount in the previous 6 months by self-reporting; Drinker: partici-pant who consumed alcohol socially or regularly regardless of the amount in the previous 6 months by self-reporting; Diabetes: fasting plasma glucose level equal to or over 126 mg/dL or a known history of diabetes with or without medication; Hypertension: having known past history or blood pressure of at least 140/90 mmHg with or without medication; Hyperlipidemia: having serum cholesterol level above 200 mg/dL, or triglyceride level 200 mg/dL or above or known past history with or without medication. Proteinuria, having+/- or heavier protein response (including+ to 4+) in urine test; Liver dysfunction: ALT level>44 IU/L; Anemia, male Hb < 13 g/dL, female Hb < 12 g/dL; Hyperu-ricemia, for both genders, serum uric acid level> 7.0 mg/dL. CKD, chronic kidney disease.
2.08, P
= 0.000). When stratified by diabetes, the adjusted
OR of CKD for non-diabetic BN users was 1.27 (95% CI
1.04–1.56, P
= 0.021). When stratified by proteinuria, the
adjusted OR of CKD for non-proteinuric BN users was 1.30
(95% CI 1.06–1.60, P
= 0.013). There were no significant
ORs in the female, drinking, diabetes and proteinuric groups.
DISCUSSION
In this cross-sectional study, we found a conditional
associa-tion of BN chewing with CKD in males, non-drinkers, and
those without diabetes or proteinuria, which is unique to
previous studies. In the current study, the overall prevalence
of CKD in BN chewers seemed to be lower than in
non-chewers (12.4% vs 16.7%). However, when the data were
stratified by age per decade (Table 3), the prevalence of CKD
in BN chewers became higher than in non-chewers in all age
groups from 40 to over 70 years, although without statistical
significance. In addition, CKD prevalence increased with age
in both the BN chewers and non-chewers groups. These
results seem to support the idea that BN chewers might have
a higher CKD prevalence. The data also raised the possibility
that other factors might be involved in the pathogenesis of
CKD. BN chewing was not considered to be a main
patho-genic factor of CKD. Instead, age was an obviously important
contributor, and, as shown in Tables 1 and 2, participants
found to have CKD also had higher prevalence of some
well-established CKD pathogenic risks such as obesity,
dia-betes, hypertension, hyperlipidemia, proteinuria, anaemia
and hyperuricemia.
The proportion of BN chewing in the CKD subjects
appeared to be lower than in participants without CKD
(Table 2). This observation does not coincide with our
hypothesis that BN chewing might be associated with CKD.
However, as also shown in Table 2, the proportion of all the
modifiable variables (including smoking, drinking and BN
chewing) appeared to be lower in the participants with CKD,
and the prevalence of all non-modifiable risk factors (DM,
HTN, hyperlipidemia) in the CKD participants was
signifi-cantly higher. It seems reasonable to infer that people might
change their health behaviours as they grew older or with
poorer health. This hypothesis is supported by Tseng’s
study,
20which reported that in older age groups, a protective
behavioural pattern was more dominant. In addition, the
Table 3 Comparison of CKD prevalence in chewers versus non-chewers stratified by age
Age range (years) CKD+ (n = 4519) P-value
Gross CKD prevalence CKD prevalence of non-chewers CKD prevalence of chewers 40~<50 299/8160 (3.7%) 265/7469 (3.5%) 34/691 (4.9%) 0.066 50~<60 454/7416 (6.1%) 415/6908 (6.0%) 39/508 (7.7%) 0.130 60~<70 1516/6385 (23.7%) 1443/6100 (23.7%) 73/285 (25.6%) 0.448 ⱖ70 2250/5521 (40.8%) 2196/5397 (40.7%) 54/124 (43.5%) 0.522
Results are expressed as n (%).
Table 4 Multivariate logistic regression analysis for post-adjustment chronic
kidney disease (CKD) odds
Odds ratio 95% confidence interval P-value
Age 1.09 1.09–1.10 0.000
Gender of male 0.82 0.76–0.89 0.000
Betel nut chewing 1.23 1.02–1.48 0.027
Smoking 1.02 0.93–1.12 0.645
Drinking 0.75 0.66–0.85 0.000
Body mass index 1.00 0.99–1.01 0.605
Hypertension 1.39 1.29–1.51 0.000 Diabetes 1.05 0.95–1.17 0.309 Hyperlipidemia 1.32 1.12–1.57 0.001 Anaemia 2.07 1.845–2.32 0.000 Proteinuria 2.43 2.19–2.69 0.000 Hyperuricemia 3.57 3.29–3.87 0.000
*P-value< 0.05; **P-value < 0.01; ***P-value < 0.001.
Table 5 Odds ratio of chronic kidney disease (CKD) with betel nut (BN)
chewing, stratified by presence and absence of variables with significant inter-action effect (gender, drinking, diabetes mellitus (DM), proteinuria)
Odds ratio 95% confidence interval P-value
Corporate a 1.23 1.02–1.48 0.027 Gender b Male 1.23 1.02–1.48 0.035 Female 0.94 0.44–2.00 0.865 Drinking b Yes 1.01 0.77–1.32 0.961 No 1.62 1.26–2.08 0.000 DM b Yes 1.11 0.73–1.69 0.621 No 1.27 1.04–1.56 0.021 Proteinuria b Yes 1.00 0.68–1.48 0.989 No 1.30 1.06–1.60 0.013
a: Multivariate logistic regression analysis conducted with all adjustment
factors, including age, gender, drinking, smoking, hypertension (HTN), DM, hyperlipidemia, hyperuricemia, body mass index, anemia and proteinuria;
b: Multivariate logistic regression analysis conducted with the rest of the
variables, in addition to specific variables under stratified conditions as presence and absence.
data in this study revealed that the proportion of BN chewing
decreased with worsening CKD severity (for CKD stage 3, 4,
and 5, the proportions of BN chewing were 4.5%, 3.7% and
1.7%, respectively). Since the questionnaire was a fixed
form authorized by the BNHI, health behaviours data were
obtained by self-reporting based on the situation in the past
6 months, so there was no access to information on a more
detailed BN chewing history (for example, the amount
con-sumed and as an ex-chewer). In addition, elderly people
might not be able to precisely remember their BN chewing
habit over the previous 5–6 months. These were potential
sources of ascertainment bias and recall bias.
As seen in Figure 1, our study results revealed a
signifi-cantly higher percentage of concurrent substance use. This is
consistent with previous research reporting that BN chewers
are more likely to use alcohol and cigarettes as well.
21Such
concurrent substance use represents certain lifestyle patterns
that might exert clusters of health effects simultaneously and
confer a higher health risk. Current relevant evidence has
reported additive effects on chronic hepatitis B, chronic
hepatitis C and hepatoma,
22oral cavity cancer,
23and calcium
urolithiasis.
24This should be dealt with seriously by the
rel-evant health authorities, for example, by sponsoring more
health education activities targeting all three risky
behav-iours at the same time.
As shown in Table 4, our study results revealed a reduced
CKD risk with alcohol drinking (OR, 0.75, 95% CI 0.66–0.85,
P
= 0.000). This is consistent with previous research
report-ing an inverse association between alcohol consumption
and renal dysfunction.
25Alcohol consumption in moderate
amounts has been acknowledged to be a protective factor for
cardiovascular health. For the kidneys, oxidative stress and
endothelial dysfunction, which are inter-related, are
consid-ered to play a role in the pathophysiology of many renal
diseases. Ethanol and non-alcoholic wine components,
espe-cially polyphenols, have been shown to influence oxidative
balance and endothelial function, and exert favourable
effects on kidneys in both animal and human studies.
26Our study found four significant interaction factors with
BN chewing: gender, drinking, DM, and proteinuria. Table 5
presents the ORs of CKD with BN chewing in the different
stratification groups. A thorough analysis of the intertwining
interactions among these factors was beyond the scope of
this article. However, as male gender constituted the
major-ity of the BN chewers, it seems reasonable that the ORs and
confidence intervals were almost identical with the overall
values. For the drinking, diabetic and
non-proteinuric groups, the ORs and confidence intervals were
similar, implying that they might be regarded as background
situations on which BN chewing exerted a similar influence.
However, when different situations (drinking, diabetes,
pro-teinuria) were involved, such significant associations
disap-peared. To our best knowledge, there is no available research
discussing the interaction effects of BN chewing and diabetes
or other health behaviours. For the diabetic patients, the
disease itself is a well-known CKD risk so that the relative
impacts of BN chewing on CKD seemed ‘buffered’ and
became non-significant. For drinkers, a lower OR of CKD
was associated with BN chewing, implying that drinking
seemed to exert a protective effect as discussed in the
previ-ous paragraph. As such, we should be cautiprevi-ous about the
interpretation of the results; the interacting effects of these
covariates on the risk of CKD with BN chewing should be
researched further.
In addition to the biases discussed earlier, there are several
other limitations to this study. This was a retrospective
cross-sectional study based on the results of a health check-up
program in a single hospital setting. Sampling and
ascertain-ment bias might arise from several aspects. First, lab
diag-noses were made with only one urine sample and blood
tests, which might not be able to validate the true renal
function. Second, the participants took the initiative to
undergo the health check-up program in this hospital, and
they might have had a higher socio-economic position or
education level, been more alert to their own health
situa-tion, or already had certain ailments, and so not be
repre-sentative of the general population. These factors were
sources of selection bias. Another limitation is that the
ques-tionnaire on health behaviours did not include detailed
quantitative assessment (duration and amount) of BN
con-sumption, nor did it include previous abstinence history.
Under such circumstances, a substantial temporal
relation-ship and dose-effect relationrelation-ship between BN chewing and
CKD cannot be concluded.
However, due to the following reasons, this study still can
provide valuable information. First, this is currently the
largest series studying the association of BN chewing and
CKD. Second, the Chia-Yi region is an area with lower
average income and a large elderly population. According to
a national statistics report, the national average proportion of
elderly people in Taiwan in 2009 was 10.6%, and the
com-peting figure in the Chia-Yi region (Chia-Yi City and Chia-Yi
County combined) was 14.0%.
27The average family income
in this area is approximately 20% lower than the national
average.
28The population in this study was therefore very
different from the populations in previous Taiwanese
Fig. 1 Comparison of the proportion of smokers and drinkers in chewing
research.
29Third, our study not only agreed with previous
research in this field,
13,14but also added more adjustment
factors (hyperuricemia and proteinuria) for MLRA, opening
a new field of IE due to life patterns, especially the effect of
alcohol drinking on kidney disease. We also found a
‘condi-tional’ association of BN chewing and CKD, which is unique
to previous studies and contributes to existing knowledge.
Further investigations are needed for prospective
longitudi-nal cohort studies, including a detailed history of BN
chewing amount, duration, and previous abstinence history.
Also, further analysis of life patterns and the complex
inter-actions of the items therein, and especially the effect of
alcohol drinking on renal health are needed.
In conclusion, BN chewing, as a personal life pattern, had
intricate interactions with gender, drinking, DM and
pro-teinuria. We found a significant association between BN
chewing and CKD in male, non-drinking, non-diabetes and
non-proteinuria; however, such results should be interpreted
cautiously. Further studies should be conducted to delineate
the relationship between BN chewing and those who drink
alcohol, and those with diabetes or proteinuria.
ACKNOWLEDGEMENTS
The authors would like to express sincere gratitude to Ms
Fang-Yun Hu and Mr Jia-En Lai for assisting with data
man-agement.
REFERENCES
1. Kuo HW, Tsai SS, Tiao MM, Yang CY. Epidemiological features of CKD in Taiwan. Am. J. Kidney Dis. 2007; 49 (1): 46–55.
2. USRDS. United States Renal Data System (USRDS) 2010 annual data report. 2010. [Cited 21 Dec 2010.] Available from URL: http://www.usrds.org/2010/ADR_booklet_2010_lowres.pdf, p 32. 3. K/DOQI clinical practice guidelines for chronic kidney disease:
Evaluation, classification, and stratification. Am. J. Kidney Dis. 2002; 39 (2 Suppl 1): S1–266.
4. Boucher BJ, Mannan N. Metabolic effects of the consumption of Areca catechu. Addict. Biol. 2002; 7 (1): 103–10.
5. Gupta PC, Warnakulasuriya S. Global epidemiology of areca nut usage. Addict. Biol. 2002; 7 (1): 77–83.
6. Ho PS, Ko YC, Yang YH, Shieh TY, Tsai CC. The incidence of oropharyngeal cancer in Taiwan: An endemic betel quid chewing area. J. Oral Pathol. Med. 2002; 31 (4): 213–9.
7. Lin WY, Chiu TY, Lee LT, Lin CC, Huang CY, Huang KC. Betel nut chewing is associated with increased risk of cardiovascular disease and all-cause mortality in Taiwanese men. Am. J. Clin. Nutr. 2008; 87 (5): 1204–11.
8. Yen AM, Chiu YH, Chen LS et al. A population-based study of the association between betel-quid chewing and the metabolic syndrome in men. Am. J. Clin. Nutr. 2006; 83 (5): 1153–60. 9. Tung TH, Chiu YH, Chen LS, Wu HM, Boucher BJ, Chen TH. A
population-based study of the association between areca nut chewing and type 2 diabetes mellitus in men (Keelung Community-based Integrated Screening programme No. 2).
Diabetologia 2004; 47 (10): 1776–81.
10. Lin WY, Pi-Sunyer FX, Liu CS et al. Betel nut chewing is strongly associated with general and central obesity in Chinese male middle-aged adults. Obesity (Silver Spring) 2009; 17 (6): 1247–54. 11. Hsiao TJ, Liao HW, Hsieh PS, Wong RH. Risk of betel quid
chewing on the development of liver cirrhosis: A
community-based case-control study. Ann. Epidemiol. 2007; 17 (6): 479–85.
12. Tseng CH. Betel nut chewing is independently associated with urinary albumin excretion rate in type 2 diabetic patients. Diabetes
Care 2006; 29 (2): 462–3.
13. Chou CY, Cheng SY, Liu JH et al. Association between betel-nut chewing and chronic kidney disease in men. Public Health Nutr. 2009; 12 (5): 723–7.
14. Kang IM, Chou CY, Tseng YH et al. Association between betelnut chewing and chronic kidney disease in adults. J. Occup. Environ.
Med. 2007; 49 (7): 776–9.
15. Pamphlet for hypertension prevention and treatment. Taipei: Bureau of Health Promotion, Department of Health, Taiwan, 2004. [Cited 20 Dec 2010.] Available from URL: http://www.bhp.doh.
gov.tw/health91/1-4-4/05 .pdf, p 10
(in Chinese).
16. Pamphlet for diabetes prevention and treatment. Taipei: Bureau of Health Promotion, Department of Health, Taiwan, 2004. [Cited 20 Dce 2010.] Available from URL: http://www.bhp.doh.gov.tw/ health91/1-3-11-1.pdf, p 13 (in Chinese).
17. Pamphlet for hyperlipidemia prevention and treatment. Taipei: Bureau of Health Promotion, Department of Health, Taiwan, 2004. [Cited 20 Dec 2010.] Available from URL: http://
www.bhp.doh.gov.tw/health91/1-5-4-04.pdf. p 41 (in Chinese). 18. Organization WH. Worldwide Prevalence of Anaemia 1993–2005.
Geneva: World Health Organization, 2008. [Cited 20 Dec 2010.] Available from URL: http://whqlibdoc.who.int/publications/2008/ 9789241596657_eng.pdf;
19. Moss CF, Sinha SR. Neurobiology of echolocation in bats. Curr.
Opin. Neurobiol. 2003; 13 (6): 751–8.
20. Tseng TS, Lin HY. Gender and age disparity in health-related behaviors and behavioral patterns based on a National Survey of Taiwan. Int. J. Behav. Med. 2008; 15 (1): 14–20.
21. Lin CF, Wang JD, Chen PH, Chang SJ, Yang YH, Ko YC. Predictors of betel quid chewing behavior and cessation patterns in Taiwan aborigines. BMC Public Health 2006; 6: 271–7.
22. Jeng JE, Tsai HR, Chuang LY et al. Independent and additive interactive effects among tumor necrosis factor-alpha
polymorphisms, substance use habits, and chronic hepatitis B and hepatitis C virus infection on risk for hepatocellular carcinoma.
Medicine (Baltimore) 2009; 88 (6): 349–57.
23. Tsai KY, Su CC, Lin YY, Chung JA, Lian Ie B. Quantification of betel quid chewing and cigarette smoking in oral cancer patients.
Community Dent. Oral Epidemiol. 2009; 37 (6): 555–61.
24. Liu CC, Huang SP, Wu WJ et al. The impact of cigarette smoking, alcohol drinking and betel quid chewing on the risk of calcium urolithiasis. Ann. Epidemiol. 2009; 19 (8): 539–45.
25. Schaeffner ES, Kurth T, de Jong PE, Glynn RJ, Buring JE, Gaziano JM. Alcohol consumption and the risk of renal dysfunction in apparently healthy men. Arch. Intern. Med. 2005; 165 (9): 1048–53.
26. Presti RL, Carollo C, Caimi G. Wine consumption and renal diseases: New perspectives. Nutrition 2007; 23 (7-8): 598–602. 27. DHR. National Statistics, 2009. Taipei: Department of Household
Registration, Ministry of the Interior, Taiwan, ROC, 2009. [Cited 22 Dec 2010.] Available from URL: http://www.ris.gov.tw/ch4/ static/y0s109800.xls (in Chinese).
28. Statistics N. The Survey of Family Income and Expenditure, 2009. Taipei: National Statistics, ROC (Taiwan), 2009. [Cited 21 Dec 2010.] Available from URL: http://win.dgbas.gov.tw/fies/doc/result/ 98/a11/49.xls
29. Hsu CC, Hwang SJ, Wen CP et al. High prevalence and low awareness of CKD in Taiwan: A study on the relationship between serum creatinine and awareness from a nationally representative survey. Am. J. Kidney Dis. 2006; 48 (5): 727–38.
