Impact of body mass index on prevalence of multimorbidity in primary care: cohort study.
BACKGROUND
Multimorbidity is the co-occurrence of long-term conditions. Obesity is associated with an increased risk of long-term conditions including type 2 diabetes and depression.


OBJECTIVE
To quantify the association between body mass index (BMI) category and multimorbidity in a large cohort registered in primary care.


METHODS
The sample comprised primary care electronic health records of adults aged ≥30 years, sampled from the Clinical Practice Research Datalink between 2005 and 2011. Multimorbidity was defined as the co-occurrence of ≥2 of 11 conditions affecting seven organ systems. Age- and sex-standardized prevalence of multimorbidity was estimated by BMI category. Adjusted odds ratios associating BMI with additional morbidity were estimated adjusting for socioeconomic deprivation and smoking.


RESULTS
The sample comprised 300 006 adults. After excluding participants with BMI never recorded, data were analysed for 223 089 (74%) contributing 1 374 109 person-years. In normal weight men, the standardized prevalence of multimorbidity was 23%, rising to 27% in overweight, 33% in category I obesity, 38% in category II and 44% in category III obesity. In women, the corresponding values were 28%, 34%, 41%, 45% and 51%. In category III obesity, the adjusted odds, relative to normal BMI, were 2.24 (2.13-2.36) for a first condition; 2.63 (2.51-2.76) for a second condition and 3.09 (2.92-3.28) for three or more conditions. In a cross-sectional analysis, 32% of multimorbidity was attributable to overweight and obesity.


CONCLUSIONS
Multiple morbidity is highly associated with increasing BMI category and obesity, highlighting the potential for targeted primary and secondary prevention interventions in primary care.
['Booth|Helen P|HP|', 'Prevost|A Toby|AT|', 'Gulliford|Martin C|MC|']
D000328:Adult D000368:Aged D000369:Aged, 80 and over D015992:Body Mass Index D002318:Cardiovascular Diseases D002908:Chronic Disease D015331:Cohort Studies D015897:Comorbidity D003920:Diabetes Mellitus D005260:Female D006801:Humans D016015:Logistic Models D008297:Male D008875:Middle Aged D015999:Multivariate Analysis D009765:Obesity D016017:Odds Ratio D050177:Overweight D011203:Poverty D015995:Prevalence D011320:Primary Health Care D012907:Smoking D012959:Socioeconomic Factors D013851:Thinness D006113:United Kingdom
obesity Cardiovascular diseases comorbidity diabetes mellitus family practice primary health care.