"Predictability of body mass index for diabetes: Affected by the presence of metabolic syndrome?"
BMC Public Health
Predictability of body mass index for diabetes: Affected by the presence of metabolic syndrome?
Farzad Hadaegh 0
Mohammadreza Bozorgmanesh 0
Maryam Safarkhani 0
Davood Khalili 0
Fereidoun Azizi
0 Prevention of Metabolic Disorders Research Center, Research Institute for Endocrine Sciences, Shahid Beheshti University of Medical Sciences , Tehran, IRAN
Background: Metabolic syndrome (MetS) and body mass index (BMI, kg.m-2) are established independent risk factors in the development of diabetes; we prospectively examined their relative contributions and joint relationship with incident diabetes in a Middle Eastern cohort. Method: participants of the ongoing Tehran lipid and glucose study are followed on a triennial basis. Among nondiabetic participants aged 20 years at baseline (8,121) those with at least one follow-up examination (5,250) were included for the current study. Multivariate logistic regression models were used to estimate sex-specific adjusted odd ratios (ORs) and 95% confidence intervals (CIs) of baseline BMI-MetS categories (normal weight without MetS as reference group) for incident diabetes among 2186 men and 3064 women, aged 20 years, free of diabetes at baseline. Result: During follow up (median 6.5 years); there were 369 incident diabetes (147 in men). In women without MetS, the multivariate adjusted ORs (95% CIs) for overweight (BMI 25-30 kg/m2) and obese (BMI30) participants were 2.3 (1.2-4.3) and 2.2 (1.0-4.7), respectively. The corresponding ORs for men without MetS were 1.6 (0.9-2.9) and 3.6 (1.5-8.4) respectively. As compared to the normal-weight/without MetS, normal-weight women and men with MetS, had a multivariate-adjusted ORs for incident diabetes of 8.8 (3.7-21.2) and 3.1 (1.3-7.0), respectively. The corresponding ORs for overweight and obese women with MetS reached to 7.7 (4.0-14.9) and 12.6 (6.9-23.2) and for men reached to 3.4(2.0-5.8) and 5.7(3.9-9.9), respectively. Conclusion: This study highlights the importance of screening for MetS in normal weight individuals. Obesity increases diabetes risk in the absence of MetS, underscores the need for more stringent criteria to define healthy metabolic state among obese individuals. Weight reduction measures, thus, should be encouraged in conjunction with achieving metabolic targets not addressed by current definition of MetS, both in every day encounter and public health setting.
diabetes prediction; metabolic syndrome; body mass index
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Background
Diabetes is a common, growing, serious, costly, and
potentially preventable public health problem [1].
Metabolic syndrome (MetS) and body mass index (BMI)
are established independent risk factors in the
development of diabetes [2]. Obesity consists of heterogeneous
phenotypes resulting from interplay between genetic and
environmental factors [3]. Increased BMI has been
associated with metabolic and cardiovascular risk factors
including diabetes, hypertension, dyslipidemia, but there
is increasing evidence that sub-phenotypes of obesity
exist that appear to deviate from the standard
doseresponse relationship between increased BMI and its
adverse clinical outcomes [4]. Metabolically obese but
normal-weight (normal-weight/MetS) is a condition to
be ascertained in individuals who despite having a
normal-weight BMI, present metabolic disturbances typical
of obese individuals. This constellation, generally known
as MetS, includes impaired insulin sensitivity, increased
visceral adiposity, low levels of high-density lipoprotein
cholesterol (HDL-C), elevated levels of fasting glucose
and triglycerides (TGs), and hypertension [5-9]. It has
been shown that the normal-weight/MetS phenotype is
associated with a three- to fourfold higher risk for
diabetes as compared with control subjects [10]. On the
other hand, metabolically healthy but obese
(obese/without MetS) individuals, have been identified who, despite
having BMI exceeding 30 kg.m-2, are relatively insulin
sensitive and have a rather favorable cardiovascular risk
profile [11-14] with a three- to fourfold lower risk for
diabetes as compared with obese insulin-resistant
individuals [10]. There has been, however, no consensus
regarding the definitions of obese/without MetS [15-18]
and the existence of a healthy obese phenotype based
on the definition of absence of MetS [19] has recently
been questioned [20]. Since no population-based study
prospectively has examined sex-specifically the joint
relationship between BMI and MetS with diabetes [10],
an unanswered question remains to be whether the
impact of diagnosis of different obesity phenotype on
prediction of incident diabetes differs by sex.
Plethora of evidences currently supports the notion
that diabetes can be prevented or the onset delayed
[21,22]. In this light, the need for evidence-based
guidelines for putting prevention into practice is seen as a
public health priority. It is, therefore, worthwhile to
clarify the combined effect of BMI and MetS for public
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