Why is diabetes increasing

Nutr Rev 1; Adiposity and hyperinsulinemia in Indians are present at birth. J Clin Endocrinol Metab ; - Neonatal anthropometry: the thin-fat Indian baby. The Pune Maternal Nutrition Study. Early life origins of insulin resistance and type 2 diabetes in India and other Asian countries.

J Nutr ; Relation of serial changes in childhood body-mass index to impaired glucose tolerance in young adulthood. N Engl J Med ;26; Prevalence of insulin resistance syndrome in a selected south Indian population— the Chennai urban population study-7 [CUPS-7]. Indian J Med Res ; Malhotra P, S. Kumari, R. Kumar, S.

Jain, N. Ganguly and B. Sharma, Hypertension and insulin resistance in a native unindustrialised rural population of India. Int J Cardiol ; Diabetes Res Clin Pract. Balkau B, Charles MA. Comment on the provisional report from the WHO consultation. Am J Epidemiol ; Relationship of glucose intolerance and hyperinsulinaemia to body fat pattern in south Asians and Europeans. The insulin resistance syndrome in Mexico.

Prevalence and clinical characteristics: a population based study. Arch Med Res ;Spec No. S9- S Epidemiological investigation of insulin resistance syndrome syndrome X in a city in Japan. Froguel P. Tracking down genes to cure diabetes: an achievable task for the 21st century?

Diabetes Metab ;23 Suppl Genetic factors in the pathogenesis of Type 1diabetes. Text book of Diabetes, Blackwell Scientific Publishers, ; Froguel P, Velho G. Genetic determinants of type 2 diabetes. Recent Prog Horm Res ; Parental transmission of Type 2 diabetes: the Framingham Offspring Study. Diabetes ; Practical Diabetes ; High prevalence of Type 2 non-insulin dependent diabetes among the offspring of conjugal Type 2 diabetic parents in India. Diab Medicine ; Diabetes Care ; Abnormalities in insulin secretion in healthy offspring of Indian patients with maturity-onset diabetes of the young.

J Assoc Physicians India ; 51; Family history of diabetes identifies a group at increased risk for the metabolic consequences of obesity and physical inactivity in EPIC-Norfolk: a population-based study.

The European Prospective Investigation into Cancer. Global Burden of cardiovascular diseases Part I: General considerations, the epidemiological transition, risk factors, and impact of urbanization. Circulation ; Impaired glucose tolerance and iabetes mellitus in a rural population in south India. Prevalence of glucose intolerance in Asian Indians. Urban-rural difference and significance of upper body adiposity. Prevalence of type 2 diabetes mellitus and risk of hypertension and coronary artery disease in rural and urban population with low rates of obesity.

Impact of poverty on the prevalence of diabetes and its complications in urban southern India. Insulin resistance and clustering of atherogenic risk factors in women belonging to low socio-economic strata in urban slums of North India. Physical activity and prevalence of diabetes in Melanesian and Indian men in Fiji. Ziv E.

In Lessons From Animal Diabetes. London, Smith- Gordon; ; Adverse physical activity pattern in urban adolescents. Obesity, fat distribution, and weight gain as risk factors for clinical diabetes in men. Anthropometry and body composition in northern Asian Indian patients with type 2 diabetes: receiver operating characteristics ROC curve analysis of body mass index with percentage body fat as standard.

Diabetes Nutr Metab ; Ehtisham S, Barrett TG. The emergence of type 2 diabetes in childhood. Ann Clin Biochem ; Bloomgarden ZT: New insights in obesity. Prevalence of obesity amongst affluent adolescent school children in Delhi. Indian Pediatr ; Size at birth, maternal weight, and type 2 diabetes in South India. Gopalan C. Type 2 diabetes is an impairment in the way the body regulates and uses sugar glucose as a fuel. This long-term chronic condition results in too much sugar circulating in the bloodstream.

Eventually, high blood sugar levels can lead to disorders of the circulatory, nervous and immune systems. In type 2 diabetes, there are primarily two interrelated problems at work.

Your pancreas does not produce enough insulin — a hormone that regulates the movement of sugar into your cells — and cells respond poorly to insulin and take in less sugar. Type 2 diabetes used to be known as adult-onset diabetes, but both type 1 and type 2 diabetes can begin during childhood and adulthood. Type 2 is more common in older adults, but the increase in the number of children with obesity has led to more cases of type 2 diabetes in younger people.

There's no cure for type 2 diabetes, but losing weight, eating well and exercising can help you manage the disease. If diet and exercise aren't enough to manage your blood sugar, you may also need diabetes medications or insulin therapy. Signs and symptoms of type 2 diabetes often develop slowly. In fact, you can be living with type 2 diabetes for years and not know it.

When signs and symptoms are present, they may include:. Exactly why this happens is unknown, but being overweight and inactive are key contributing factors.

Insulin is a hormone that comes from the gland situated behind and below the stomach pancreas. Insulin regulates how the body uses sugar in the following ways:. Glucose — a sugar — is a main source of energy for the cells that make up muscles and other tissues. The use and regulation of glucose includes the following:.

In type 2 diabetes, this process doesn't work well. Instead of moving into your cells, sugar builds up in your bloodstream. As blood sugar levels increase, the insulin-producing beta cells in the pancreas release more insulin. Data from various sources were obtained to draw a repeated cross-sectional — description of these factors concurrently with changes in the prevalence of type 2 diabetes in New Brunswick.

Linear regressions, Poisson regressions and Cochran Armitage analysis were used to describe relationships between these factors and time. Factors identified in the review were summarized in five categories: individual-level risk factors, environmental risk factors, evolution of the disease, detection effect and global changes.

The prevalence of obesity, hypertension, prediabetes, alcohol consumption, immigration and urbanization increased during the study period and the consumption of fruits and vegetables decreased which could represent potential factors of the increasing prevalence of type 2 diabetes.

Physical activity, smoking, socioeconomic status and education did not present trends that could explain the increasing prevalence of type 2 diabetes. During the study period, the mortality rate and the conversion rate from prediabetes to diabetes decreased and the incidence rate increased. Suggestion of a detection effect was also present as the number of people tested increased while the HbA 1c and the age at detection decreased.

Period and birth cohort effect were also noted through a rise in the prevalence of type 2 diabetes across all age groups, but greater increases were observed among the younger cohorts. This study presents a comprehensive overview of factors potentially responsible for population level changes in prevalence of type 2 diabetes. Recent increases in type 2 diabetes in New Brunswick may be attributable to a combination of some individual-level and environmental risk factors, the detection effect, the evolution of the disease and global changes.

With million people living with diabetes in [ 1 ], the World Health Organization declared the condition as being epidemic [ 2 ].

It is estimated that diabetes will affect 3. Diabetes is associated with many health complications. Annual per capita healthcare costs for people with diabetes are three to four times greater than for individuals without diabetes [ 3 ]. New Brunswick is one of the provinces in Canada where the prevalence of diabetes is the highest [ 3 ]. A population-level increase in prevalence of diabetes may be attributable to a wide range of potential factors [ 5 — 7 ].

Obesity is often seen as the main contributor to an increasing prevalence of diabetes [ 8 — 10 ] but other factors such as ageing, ethnicity, lifestyle i. Further findings also suggest that increasing incidence rates of diabetes [ 15 — 18 ] and global changes are other potential explanatory factors e. In addition to changes in the prevalence of risk factors, other elements, including increases in screening [ 10 ], changes in diagnostic criteria [ 21 ], and decreasing mortality rates among individuals with diabetes [ 15 — 18 , 22 — 32 ] could contribute to the rise in prevalence of this condition.

Perhaps due to the wide variety of factors potentially responsible for an increase in prevalence of diabetes, no studies have attempted to present a comprehensive list of factors which could be responsible for population-level changes in prevalence of diabetes.

A comprehensive list of factors that contribute to the growing prevalence of diabetes would provide a foundation for population health planning in developing successful strategies to address this epidemic of diabetes. As such, the objectives of this study were 1 to develop a comprehensive list of factors to consider when trying to identify causes of change in prevalence of diabetes in a population and 2 to use this list to describe factors that may be responsible for the recent increase in prevalence of type 2 diabetes in New Brunswick.

A critical review of the literature was conducted to identify all factors potentially involved in explaining changes in the prevalence of diabetes. A critical review includes an extensive research of the literature and an evaluation of its quality without a systematic research approach [ 33 ].

This type of review includes a description of identified articles, synthesizes and analyzes the information to develop an hypothesis or a model for further study [ 33 ]. The first step of the critical review was to identify studies that aimed to document a wide range of factors explaining changes in the prevalence of diabetes. The second step of the critical review searched studies that described other factors without restricting to only review articles.

From the articles of the first research procedure and of the second, were duplicates. Of the unique articles, we retained six review articles that presented multiple potential determinants of diabetes prevalence.

In total, 77 articles were included in this critical review. De-identified registries of all individuals with diabetes and all individuals with prediabetes were created from New Brunswick Department of Health administrative datasets and were stored in a secured office within the New Brunswick Health Council. Those administrative datasets included the list of all New Brunswickers with provincial healthcare coverage all Canadian residing in New Brunswick and a repository of all HbA 1c tests conducted between and Similarly, individuals were identified as having prediabetes the first time they had a HbA 1c test between 6.

This approach is used by the New Brunswick Department of Health for their provincial reports and has been used by other authors [ 6 ] since diabetes cases diagnosed before this age are more often type 1 diabetes [ 34 ]. Prevalence of diabetes and prediabetes were measured annually as the proportion of individuals with diabetes and the proportion of individuals with prediabetes divided by their respective populations at risk during the fiscal year, defined as April 1st to March 31st.

The population at risk was determined based on the number of New Brunswickers aged 30 or older recorded from the annual estimates of the population from Statistics Canada. The denominator for incidence rates corresponded to the at-risk population described above minus the prevalent cases and incident cases during the year. Mortality rate corresponded to the number of people with diabetes who died during the fiscal year.

The denominator included all people living with diabetes, including the time alive among those who died within the given year. The conversion rate from prediabetes to diabetes was calculated as the number of individuals with prediabetes who developed diabetes during the fiscal year over the number of individuals with prediabetes. Number of people with HbA 1c testing was defined annually as the number of people with at least one HbA 1c test during the fiscal year.

Age at detection was derived from the date at which the first test attained the diagnostic threshold and the documented birth date of the individuals. HbA 1c at detection was obtained by averaging the HbA 1c value at detection of all incident cases for each fiscal year. The breakdown of the population by age groups was obtained from to from annual estimates of the entire New Brunswick population from Statistics Canada.

The prevalence of select risk factors was determined from self-reported information available for the New Brunswick population from the Canadian Community Health Survey in , and annually from to for people aged 35 years old and greater.

Level of education number of people who completed high school; number with a university degree was obtained from the Labour Force Survey from to Socioeconomic status percentage of people having low income before taxes was available from to from the Income Statistics Division of Statistics Canada and urbanization people living in a rural area, defined as any territory situated outside population centers which contain a population of at least person and a density of or more person by square kilometer was obtained from Census data for , and Ethnicity percentage of immigration used as a proxy for ethnicity herein was also obtained from Census data for and and from the National Household Survey for Cochran—armitage analyses of trend were used to assess the association between time fiscal year and variables represented as yearly prevalence.

Poisson regressions were used to assess associations between time and mortality rate and between time and conversion rate from prediabetes to diabetes. Linear regressions were used to assess time trends in number of people who undergone HbA 1c testing, the average value of HbA 1c and the average age at detection. Assessing for the presence of a birth cohort effect was also done by calculating the prevalence of diabetes among decade-of-birth-based cohorts —, …, — for each fiscal year.

From , individuals identified with diabetes in the registry between and , 97, individuals were included because they were diagnosed at 30 years old or older. The prevalence of type 2 diabetes increased by an average of 6. The critical literature review identified several factors that could potentially explain such a change in the prevalence of diabetes at a population level. The factors have been grouped in five categories Table 2 which are defined below.

A description of these factors from to in New Brunswick is also presented to better understand how they could have contributed to the rise in prevalence of diabetes in this region.

In Table 2 , factors for which we found information and which we included in the analyses are presented in italics. Concurrently, we noted a marked increase in the prevalence of prediabetes from to Table 1.

Increases were also noted in the prevalence of obesity, hypertension, alcohol consumption, and immigration over the same period of time. During the study period, we also found the population was aging and that the prevalence of consumption of fruits and vegetables decreased. However, the proportion of people reporting a physically active lifestyle, sedentary behaviours, tobacco smoking, having completed high school and university education, and being of low income evolved in directions that were opposite to the direction expected to be considered as a factor contributing to the increasing prevalence of diabetes.

The literature review has shown that some environmental risk factors such as the presence of environmental pollutants such as nitrogen dioxide NO 2 , particulate matter PM , organic persistent pollutants and non-persistent pesticides , urbanization and rapid socioeconomic development could explain part of the increase in the prevalence of diabetes.

In this study, the only factor that was possible to measure was the urbanization based on the proportion of people living in a rural area. This proportion decreased during the study period and evolved in a direction supporting that it may have influenced the increase in prevalence of diabetes in New Brunswick Table 1. Some factors characterizing the evolution of the disease, including survival time among individuals with diabetes, number of new cases of diabetes and conversion to diabetes from prediabetes population, could explain the increase in the prevalence of diabetes.

In this study, we found that only two of these factors evolved in the direction expected if these factors were to explain the increase in prevalence of diabetes. The incidence rate increased from to and a higher increase in the incidence rate was seen around and Table 1. The mortality rate of the population with diabetes decreased in the same period.

In contrast, the conversion rate from prediabetes to diabetes could not explain the increase in prevalence of diabetes because it decreased during this period. The literature review also suggested that a change in prevalence of disease could be attributed to changes in how the condition is identified.

The detection effect could be related to an increase in the number of people being screened or diagnosed, an earlier detection of the disease and changes in diagnostic criteria. Accordingly we found that the number of people tested for HbA 1c increased from to and showed a higher increase around and Fig. Concurrently, the mean HbA 1c at detection decreased between and suggesting that people are being diagnosed earlier in the evolution of the disease Table 1.

It was also noted that the percentage of individuals with diabetes previously identified with prediabetes increased from to , also suggesting that people are being detected at an earlier stage of their disease. The average age at detection also supports the presence of a detection effect since data suggest that people are being diagnosed at a younger age. Changes in factors could also be more pronounced in segments of the population, based on the year of birth birth cohort effect.

In this study, the presence of a period effect was supported by an increase in the prevalence of type 2 diabetes from and in each age group, with the 40—49 year old age group displaying a greater increase Fig. The presence of a birth cohort effect was also suggested since the increase in prevalence of type 2 diabetes was considerably greater among the youngest birth cohort compared to the oldest birth cohorts Fig.

The prevalence of type 2 diabetes has more than doubled in the past 15 years in New Brunswick. Although this prevalence change is relatively greater than changes noted elsewhere, this is consistent with the increase in prevalence in diabetes observed in recent years in other provinces and countries around the world [ 69 , 72 ].

To help identify factors responsible for this increase, our literature review led to the identification of five categories of factors which together represent a comprehensive overview of factors that could explain a change in prevalence of diabetes. Our review included considerably more potential factors than what had been reported in other literature reviews [ 5 — 7 , 35 , 57 , 73 ].

Guided by this inventory, we assessed the changes in nearly all factors suggested to potentially influence the prevalence of diabetes in New Brunswick. Through this work, we identified that changes in prevalence of diabetes in New Brunswick are likely attributed to a combination of numerous factors.

Among individual-level risk factors identified in the critical review, our analysis suggests that the presence of other conditions, such as the aging population, obesity, hypertension and prediabetes could contribute to explain the increase in prevalence of type 2 diabetes in New Brunswick.

Furthermore, although immigration increased in NB, it is difficult to conclude that ethnicity might have an effect on the prevalence of type 2 diabetes in NB since no information is available on ethnic origin of immigrants in the databases used.

An increase in prevalence of obesity or body mass index has been linked to increases in the prevalence of diabetes in many other studies [ 8 , 37 — 39 , 68 ] and authors suggested it is the most important contributor to increases in prevalence of diabetes [ 8 — 10 ]. Consistent with changes in body composition of the population, we also noted that diet quality decreased over the study period.

However, our data suggest that New Brunswickers became more physically active in the past 15 years, which does not concord with trends for obesity and diabetes. It has been suggested that this discrepancy may be attributable to measurement error associated with the use of self-reported measures [ 74 ]. Self-reported measures, such as physical activity levels, are suspected to have been influenced by an increase in social desirability possibly creating higher estimates over the years [ 74 ].

However, our results are consistent with the apparent increase in prevalence of a physically active lifestyle in the United States from and , which seems to have had minimal impact on reducing the burden of obesity [ 75 ]. Among the potential for environmental risk factors to have influenced diabetes, we only had access to data relating to urbanization and these suggested that the transition from a predominantly rural to an urban population accompanied the increase in prevalence of diabetes in New Brunswick.

This transition may mean that a greater proportion of the population may be exposed to obesogenic environments such as more sedentary work, higher use of car and public transport, television viewing and in short, lower levels of physical activity [ 6 ]. Although environmental pollution can be present in rural regions, it is also possible that urbanization has led to more exposure to pollutants.

A meta-analysis has shown that the prolonged exposition to nitrogen dioxide NO 2 , particulate matter less than 2. Changes in how diabetes evolves may also contribute to explaining a change in how the prevalence of disease increased in New Brunswick. Most particularly, we noted a decline in mortality rates of people with diabetes from to , which is consistent with results from other studies [ 18 , 22 , 23 , 26 — 28 , 31 ]. A longer survival period in the population with diabetes, likely explained by better treatment and control of the disease [ 48 ], therefore contributed to the increase in prevalence.

An increase in the conversion rate from prediabetes to diabetes could also have explained an increase in diabetes prevalence [ 65 ]. However, this study shows a decrease in the conversion rate from prediabetes to diabetes, therefore suggesting either better prevention efforts in this population at risk or a relatively higher proportion of people identified with prediabetes through more screening.

As our data indicated, it is highly probable that part of the increase in prevalence of diabetes can be attributed to a detection effect whereby the number of people tested with HbA 1c rose markedly during the study period. Although the increase in testing was observed every year, sharper increases appeared to coincide with milestones such as the publication of the and guidelines encouraging type 2 diabetes screening [ 76 , 77 ] and the identification of HbA 1c as a recognised diagnostic tool by the American Diabetes Association in [ 78 ].

The possibility of earlier detection of the disease is also supported by a decrease in HbA 1c levels and age at detection during the study period. The increase in testing and an early detection may also partly be explained by the study period corresponding with the introduction of financial incentives for physicians to offer recommended care to their patients with diabetes , the implementation of an HbA1c tracking tool created to improve adherence to guidelines [ 79 ] and the Physician Practice profiles implemented in to aid physicians to identify at risk patients in New Brunswick.

The fact that an increase in the prevalence of type 2 diabetes was observed in all age groups over the 15 years of study supports the presence of a period effect. The percentage of change in the prevalence of diabetes was nevertheless higher among the 40—49 years old, as it is possible that this group benefited from a higher detection effect than other age groups.

The period effect could be attributed to a combination of any of the other factors identified in this study, including urbanization, increases in immigration and an increase in the detection. Other factors not measured, such as rapid socioeconomic development and increase in environmental pollution, could also be at play [ 19 ]. The data also presented evidence of a birth cohort effect as we observed higher increases in the prevalence of type 2 diabetes in the younger cohort groups.

This could be explained by exposure early in life to some environmental factors related to an increase in obesity, as suggested by Soon et al. These results are consistent with others who demonstrated that steeper increases in the prevalence of diabetes in the youngest cohort parallel increases in the prevalence of obesity in the younger generations [ 19 , 20 ]. The development of more obesogenic environment may affect younger people to a greater extent than other age groups since it represents a great proportion of their relative environmental exposure [ 19 ].

Further, another study reported that weight gain between 25 and 40 years old was associated with a higher risk of diabetes than a weight gain after 40 years old [ 80 ]. The present study has some limitations that need to be acknowledged.