Dying for a smoke: how much does differential mortality of smokers affect estimated life-course smoking prevalence?

Objective

An extensive literature uses reconstructed historical smoking rates by birth-cohort to inform anti-smoking policies. This paper examines whether and how these rates change when one adjusts for differential mortality of smokers and non-smokers.

Methods

Using retrospectively reported data from the US (Panel Study of Income Dynamics, 1986, 1999, 2001, 2003, 2005), the UK (British Household Panel Survey, 1999, 2002), and Russia (Russian Longitudinal Monitoring Study, 2000), we generate life-course smoking prevalence rates by age-cohort. With cause-specific death rates from secondary sources and an improved method, we correct for differential mortality, and we test whether adjusted and unadjusted rates statistically differ. With US data (National Health Interview Survey, 1967-2004), we also compare contemporaneously measured smoking prevalence rates with the equivalent rates from retrospective data.

Results

We find that differential mortality matters only for men. For Russian men over age 70 and US and UK men over age 80 unadjusted smoking prevalence understates the true prevalence. The results using retrospective and contemporaneous data are similar.

Conclusions

Differential mortality bias affects our understanding of smoking habits of old cohorts and, therefore, of inter-generational patterns of smoking. Unless one focuses on the young, policy recommendations based on unadjusted smoking rates may be misleading.     

Smoking prevalence and smoking attributable mortality in Italy, 2010

Objective

To provide updated information on smoking prevalence and attributable mortality in Italy.

Method

A representative survey on smoking was conducted in 2010 on a sample of 3020 Italian adults (1453 men and 1567 women). We used SAMMEC software to update smoking attributable mortality in Italy.

Results

In 2010, 21.7% of Italians (23.9% of men and 19.7% of women) described themselves as current smokers. Smoking prevalence was higher in men than in women in all age groups, except for the middle-aged population (45-64 years; 25.6% in men and 25.9% in women). Age-standardized smoking prevalence was higher in men than in women among less educated subjects and in southern Italy. No substantial difference was observed either in educated subjects or in northern and central Italy. Overall, 71,445 deaths in Italy (52,707 men and 18,738 women, 12.5% of total mortality) are attributable to smoking.

Conclusion

The overall smoking prevalence of 21.7% in 2010 is the lowest registered over the last 50 years. Since 1998, smoking related deaths declined by almost 15%. Given that Italy has now reached the final stage of the tobacco epidemic, anti-smoking strategies should focus on support for smoking cessation.     

Associations of smoking and smoking cessation with CT-measured visceral obesity in 4656 Korean men

Objectives

Although obesity is shown to be less common among current smokers than never smokers, the association between visceral obesity and smoking remains uncertain.

Methods

For this cross-sectional analysis, we recruited 4656 Korean men of 19 to 79 years who received a regular checkup at a health examination center between 2008 and 2010. Computed tomography was performed to measure the area of visceral and subcutaneous adipose tissue (VAT and SAT). We compared the mean VAT by multiple regression analysis across smoking status after adjusting for confounders.

Results

Both current and former smokers had more mean VAT than never smokers. Current smokers who consumed more than 20 cigarettes per day had 11% higher mean VAT than never smokers (P < 0.01). Longer smoking duration, higher daily cigarette consumption before quitting, and shorter abstinence duration among ex-smokers were associated with increasing mean VAT (all P for trend < 0.01). The mean VAT in former smokers was highest within 2 years of abstinence. There was no significant difference of mean VAT between ex-smokers with > 20 years of abstinence duration and never smokers.

Conclusion

Both current and former smoking is associated with increased VAT. The risk of visceral obesity is proportional to the degree of exposure to cigarette smoking.     

Impacto de la Ley 28/2005 de medidas sanitarias frente al tabaquismo en la prevalencia de la exposición al humo ambiental del tabaco en Barcelona

Objective

To assess the impact of the 28/2005 Spanish smoking law on exposure to second-hand smoke (SHS) in Barcelona.

Methods

We performed a pre-post evaluation study. Two cross-sectional surveys were compared. Data were obtained from the Barcelona Health Surveys of 2000 and 2006. The prevalence of SHS exposure among non-smoking adults was analyzed by setting (home, workplace and leisure time) and sociodemographic variables.

Results

SHS exposure in non-smokers significantly decreased between 2000 and 2006 (p <0.01). Odds ratios adjusted by sex, age and social class were 0.7 (95% CI: 0.6-0.8) for home and 0.2 (95% CI: 0.2-0.3) for workplace exposure in 2006 compared with 2000. In both settings, the decrease in exposure was greater in the higher social classes. After the implementation of the law, almost 50% of the population remained exposed to SHS during leisure time, younger people being the most exposed (83.5%).

Conclusion

After the implementation of the law, the prevalence of SHS exposure in non-smokers in Barcelona decreased significantly in workplaces and in the home. Nevertheless, nearly half of the population remained exposed to SHS during leisure time.     

Money as motivation to quit: a survey of a non-random Australian sample of socially disadvantaged smokers' views of the acceptability of cash incentives

Objective

This study aimed to a) assess acceptability of personal financial incentives to socially disadvantaged smokers and non-smokers; b) examine factors associated with acceptability; and c) examine preferred levels of incentive amounts.

Methods

A cross-sectional touch screen computer survey was conducted between February and October 2010 in New South Wales, Australia. Participants were clients experiencing financial or social hardship and receiving emergency welfare aid from a non-government social and community service organisation.

Results

Of 383 participants (69% response rate), 46% believed personal financial incentives were an excellent/good idea, 47% believed personal financial incentives did more good than harm and 61% agreed they would motivate smokers to quit. High acceptability ratings were associated with participants being female, current smokers, living in low socioeconomic areas, experiencing smoking-induced deprivation, making a previous quit attempt and intending to quit in the next 6 months. When asked what amount of incentive they felt would be acceptable, 23% selected amounts between $50 and $500AUD and 37% selected amounts over $500AUD.

Conclusions

Given high smoking prevalence among socially disadvantaged groups and consequent health disparities, it is imperative novel methods of encouraging smoking cessation are explored and tested. This survey found financial incentives may be an acceptable method. Further research to understand all possible positive and negative effects is warranted.     

Variations in body mass index of users of depot-medroxyprogesterone acetate as a contraceptive

Background

Weight gain is a frequent reason for discontinuing the contraceptive with depot-medroxyprogesterone acetate (DMPA).

Study Design

This 3-year retrospective cohort study assessed body mass index (BMI; kg/m²) variations in 379 current or past DMPA users compared to TCu380A intrauterine device (IUD) users matched for age and BMI, categorized into G1 (normal weight), G2 (overweight) or G3 (obese) according to baseline BMI. Variations in weight and BMI were evaluated using analysis of variance.

Results

BMI increased progressively in all groups but significantly more in G1 and G2 DMPA users compared to nonusers and according to duration of use. In the G3 subgroup, weight trends were similar in the DMPA and IUD users.

Conclusions

Normal and overweight women increased BMI with DMPA use; however, obese women did not increase weight. Weight increase in DMPA users could be associated with metabolic alterations related to duration of use in normal and overweight women and to alterations already present in obese women. Prospective studies are required to determine triggering factors. DMPA use ≤3 years was not associated with weight increase in women with BMI (kg/m²) ≥30.     

Prospective association between body mass index and receipt of preventive services: results from the Central Pennsylvania Women's Health Study (CePAWHS)

Objective

We examine whether overweight and obesity are associated with disparities in clinical preventive services receipt in a unique, prospective, population-based cohort of reproductive-age women.

Method

We used data from the Central Pennsylvania Women's Health Study (CePAWHS) longitudinal survey of women ages 18-45. The baseline random-digit-dial telephone survey was conducted in 2004-2005 and a second telephone interview two years later; 1342 participants comprised the analytic sample. Dependent variables were seven preventive services identified at follow-up. In addition to baseline body mass index (BMI) category, independent variables were selected based on the behavioral model of health services utilization.

Results

Forty-six percent of the sample was classified as normal weight, 28% as overweight, and 26% as obese. In adjusted analyses, women who were overweight and obese, compared to women with normal weight, were more likely to receive preventive counseling for diet/nutrition, physical activity, and weight management (p < 0.01). Overweight and obese women received more cholesterol and diabetes screening (p < 0.05 and p < 0.01, respectively). However, there were no differences by BMI category in receipt of Pap testing or reproductive counseling.

Conclusion

Overall, we found that women with overweight and obesity were more likely to receive preventive services, especially services relevant for overweight and obese populations.     

The association between smoking and body mass index: results from a national sample of Malaysian adults

Aim

To investigate the association between smoking status and body-mass-index (BMI) categories.

Subject and methods

Data are obtained from 2,340 observations from the Malaysia Non-Communicable Disease Surveillance-1. An ordered probability model for BMI categories with ordinal smoking treatment categories is developed and estimated. Marginal and treatment effects are calculated.

Results

Socio-demographic and health-lifestyle factors play significant roles in body weight categories, conditional upon smoking status. Education levels are inversely correlated with BMI categories amongst non-smokers only. Age and income levels are associated with BMI within non-smokers and compulsive smokers. Gender (female), family history of serious illnesses, individual health conditions (hypercholesterolemic, hypertensive), ethnicity (Malays and Indians) and regional locations (metropolitan) are associated with higher BMI levels, irrespective of smoking status. Additionally, BMI categories and levels are closely associated with smoking habits. As individuals switch from non-smoking to casual smoking, the probability of being overweight or obese increases, with an upsurge of 1.89 BMI units. As the casual smoking habit evolves into compulsive smoking, overweight or obese likelihoods are lowered as individuals are more likely to be in the underweight, normal weight or at-risk weight BMI ranges instead, while experiencing a decline of 1.75 BMI units.

Conclusions

There exists close association between BMI categories and levels with smoking habits. As smoking tendencies develop from being a non-smoker to a casual (compulsive) smoker, overweight or obese likelihoods increase (decrease), as individuals realize an upsurge (reduction) in BMI levels.     

Presence of an interaction between smoking and being overweight increases risks of hypertension, diabetes, and cardiovascular disease in outpatients with mood disorders

Objective

We aimed to evaluate the hypothesis that the presence of an interaction between smoking and being overweight increases the risks of lifestyle-related diseases (hypertension, diabetes mellitus, dyslipidemia, and cardiovascular disease) in outpatients with mood disorders.

Methods

In this cross-sectional survey, using data from 213 outpatients with mood disorders (95 men, 118 women), we calculated the adjusted odds ratios (ORs) with 95% confidence intervals (CIs) for each of hypertension, diabetes, dyslipedemia, and cardiovascular disease, using a binary logistic regression model; we then calculated the adjusted OR values for smokers and non-smokers with body mass indexes (BMIs) of <25 or ≥25 kg/m². Next, we examined the data for the presence of an interaction between smoking and being overweight, using three measures of additive interaction: relative excess risk due to the interaction (RERI), attributable proportion due to the interaction (AP), and the synergy index (S).

Results

Smokers with BMI <25 kg/m² had a significantly lower risk of hypertension (OR 0.27, 95% CI 0.09–0.81) than non-smokers with BMI <25 kg/m² (reference group). Compared with the reference group, overweight non-smokers had a significantly higher risk (2.82, 1.34–6.19) of hypertension, and overweight smokers had a higher risk (4.43, 1.28–15.26) of hypertension and very high risks of diabetes (8.24, 2.47–27.42) and cardiovascular disease (13.12, 1.95–88.41). The highest RERI was derived from the relation with cardiovascular disease. The highest AP and S were derived from the relation with type 2 diabetes. There was no interaction of smoking and being overweight with dyslipidemia.

Conclusion

The presence of an interaction between smoking and being overweight exacerbates the risks of hypertension, diabetes, and cardiovascular disease in outpatients with mood disorders.     

BMI trajectory groups in veterans of the Iraq and Afghanistan wars

Objective

The study sought to determine BMI trajectories in Iraq/Afghanistan veterans over 6 years and to examine sociodemographic factors associated with BMI trajectory membership.

Methods

Our study sample included 16,656 veterans post-deployment and entering the Veteran Healthcare Administration (VHA) healthcare system. We used national VHA administrative sociodemographic data, tracked veteran BMI for 6 years, and used trajectory modeling to identify BMI trajectories and sociodemographic characteristics associated with trajectory membership.

Results

Five trajectory groups determined in the full sample were primarily differentiated by their post-deployment initial BMI: "healthy" (14.1%), "overweight" (36.3%), "borderline obese" (27.9%), "obese" (15.7%), and "severely obese" (6.0). Being female, younger, and white were associated with lower initial BMI trajectory group membership (p's < .05). Greater observed BMI increase was associated with higher initial BMI across groups (0.6, 0.8, 1.5, 1.9, 2.7). Gender specific trajectory models found that male Veterans with higher education and white female Veterans were associated with the lowest initial BMI group (p's < .05).

Conclusions

Higher post-deployment BMI was associated with greater BMI gain over time for both male and female veterans. Older age is associated with higher BMI regardless of gender. Education level and racial status are differentially related to BMI trajectory by gender.     

Carbohydrate Intake and Overweight and Obesity among Healthy Adults

Background

Little is known about the dietary habits of people with optimal body weight in communities with high overweight and obesity prevalence.

Objective

To evaluate carbohydrate intake in relation to overweight and obesity in healthy, free-living adults.

Design

We used a cross-sectional analysis.

Subjects/setting

The Canadian Community Health Survey Cycle 2.2 is a cross-sectional survey of Canadians conducted in 2004-2005. There were 4,451 participants aged 18 years and older with anthropometric and dietary data and no comorbid conditions in this analysis.

Main outcome measures

Outcome variables were body mass index (BMI; calculated as kg/m²) and overweight or obesity status (dichotomous) defined as BMI ≥25 compared with BMI <25 based on measured height and weight. Diet was evaluated by 24-hour dietary recall based on the Automated Multi-Pass Method.

Statistical analyses performed

Weighted regression models with bootstrapping and cubic splines were used. Outcome variables were BMI and overweight or obesity, and predictors were daily nutrient intake. Adjustment for total energy intake, age, leisure time energy expenditure, sex, smoking, education, and income adequacy was performed.

Results

Risk of overweight and obesity was decreased in all quartiles of carbohydrate intake compared to the lowest intake category (multivariate odds ratio quartile 2=0.63; 95% confidence interval: 0.49 to 0.90; odds ratio quartile 3=0.58; 95% confidence interval: 0.41 to 0.82; odds ratio quartile 4=0.60; 95% confidence interval: 0.42 to 0.85). Spline analyses revealed lowest risk among those consuming 290 to 310 g/day carbohydrates.

Conclusions

Consuming a low-carbohydrate (approximately <47% energy) diet is associated with greater likelihood of being overweight or obese among healthy, free-living adults. Lowest risk may be obtained by consuming 47% to 64% energy from carbohydrates.     

Motives to quit smoking and reasons to relapse differ by socioeconomic status

Objective

To investigate motives, strategies and experiences to quit smoking and reasons to relapse as a function of socioeconomic status.

Methods

A population-based study, Inter99, Denmark. Two thousand six hundred twenty-one daily smokers with a previous quit attempt completed questionnaires at baseline. Cross-sectional baseline-data (1999-2001) were analysed in adjusted regression analyses.

Results.

Consistent findings across the three indicators of socioeconomic status (employment, school education, higher education/vocational training): smokers with low socioeconomic status were significantly more likely than smokers with high socioeconomic status to report that they wanted to quit because smoking was too expensive (OR: 1.85 (1.4-2.4), for school education) or because they had health related problems (OR: 1.75 (1.4-2.2)). When looking at previous quit attempts, smokers with low socioeconomic status were significantly more likely to report that it had been a bad experience (OR: 1.41 (1.1-1.8)) and that they had relapsed because they were more nervous/restless/depressed (OR: 1.43 (1.1-1.8)).

Conclusions.

This study shows that smokers with low socioeconomic status have other motives to quit and other reasons to relapse than smokers with high socioeconomic status. Future tobacco prevention efforts aimed at smokers with low socioeconomic status should maybe focus on current advantages of quitting smoking, using high cost of smoking and health advantages of quitting as motivating factors and by including components of mental health as relapse prevention.     

Transitions between the stages of smoking in Iranian adolescents

Objective

This study examined the prevalence of smoking, the rates of transitions, and predictors of transition through the three stages of smoking.

Methods

A total of 1785 high school students in Tabriz (northwest of Iran) were assessed at 2 time points with a 12-month interval in 2005 and 2006, regarding changes in smoking stages. The predictor variables were measured when the students were in the 10th grade. Logistic regression was employed to predict the different smoking stages at grade 11.

Results

The results showed that 14.3% (95% confidence interval, 12.3%-16.4%) and 2.8% (2.0%-4.0%) of the never smokers became experimenters and regular smokers, respectively, whereas 16.5% (12.4%-21.7%) of the experimenters became regular smokers. Among never smokers, participation in groups with at least one smoker (odds ratio, 1.24 (95% confidence interval, 1.05-1.47)), having smoker friends (1.85 (1.21-2.83)), and a positive attitude toward smoking (1.22 (1.02-1.46)) predicted smoking experience. Among the experimenters, those who had general risk behaviors (2.56 (1.12-5.87)) and participated in groups with at least one smoker (2.58 (1.26-5.31)) significantly progressed to becoming a regular smoker at the follow-up.

Conclusion

Prevention of smoking in adolescence should begin by focusing on the predictors of transition through smoking stages, especially participating in smoker groups.     

Associations between multiple indicators of objectively-measured and self-reported sedentary behaviour and cardiometabolic risk in older adults

Objective

To examine the associations between sedentary behaviour (SB) measured objectively and by self-report and cardiometabolic risk factors.

Method

Cross-sectional analyses of adults ≥ 60 years who participated in the 2008 Health Survey for England. Main exposures were self-reported leisure-time SB consisting of TV/DVD viewing, non-TV leisure-time sitting, and accelerometry-measured SB. Outcomes included body mass index (BMI), waist circumference, cholesterol ratio (total/HDL), Hb1Ac and prevalent diabetes.

Results

2765 participants (1256 men) had valid self-reported SB and outcomes/confounding variables data, of whom 649 (292 men) had accelerometer data. Total self-reported leisure-time SB showed multivariable-adjusted (including for moderate-to-vigorous physical activity) associations with BMI (beta for mean difference in BMI per 30 min/day extra SB: 0.088 kg/m², 95% CI 0.047 to 0.130); waist circumference (0.234, 0.129 to 0.339 cm); cholesterol ratio (0.018, 0.005 to 0.032) and diabetes (odds ratio per 30 min/day extra SB: 1.059, 1.030 to 1.089). Similar associations were observed for TV time while non-TV self-reported SB showed associations only with diabetes (1.057, 1.017 to 1.099). Accelerometry SB was associated with waist circumference only (0.633, 0.173 to 1.093).

Conclusion

In older adults SB is associated with cardiometabolic risk factors, but the associations are more consistent when is measured by self-report that includes TV viewing.     

Population attributable numbers and fractions of deaths due to smoking: a pooled analysis of 180,000 Japanese

Objective

Age- and sex-specific population attributable fraction (PAF) and premature deaths attributable to smoking were estimated from a pooled analysis of cohort studies in Japan.

Methods

A pooled analysis of individual participant data from 13 well-qualified cohort studies throughout Japan (a total of 183,251 Japanese aged 40-89, 69,502 men and 113,749 women; the baseline years between 1987 and 1995 with average 10 years of follow-up) was performed. Poison regression model was used to estimate age- and sex-specific hazard ratios, and their PAFs of all-cause deaths and number of annual premature deaths attributable to smoking were estimated.

Results

Overall PAF attributable to smoking was 24.6% in men and 6.0% in women. The estimated number of annual premature deaths due to smoking was 121,854 (men: 109,998; women: 11,856) in Japan. The age-specific PAF was largest in men aged 60-69 (47.7%) and in women aged 50-59 (12.2%). In the older group aged 70-79 and 80-89, PAF was 15.4% and 8.0% in men and 3.5% and 1.5% in women, respectively.

Conclusions

Age-specific PAFs attributable to smoking in Japanese men are much larger than that reported from other Asian countries.     

Contraceptive use by obese women 1 year postpartum

Background

Obese women have higher rates of pregnancy complications, making the prevention of unintended pregnancies in this group of particular importance.

Study Design

We performed a secondary analysis of data from Active Mothers Postpartum (AMP), a randomized controlled trial aimed at postpartum weight reduction. We assessed contraceptive use among 361 overweight/obese women 12 months postpartum. Logistic regression was used to model the effect of body mass index (BMI) categories on effective contraceptive use (intrauterine, hormonal or sterilization methods) while adjusting for potential confounders including age, race, parity, breastfeeding, education and chronic illness.

Results

Effective contraceptive use was reported by 45% of women. In the multivariable model, women with a BMI ≥35 kg/m² were less likely to use effective contraception than women with a BMI <30 kg/m² (OR 0.5, 95% CI 0.3-0.8). There was a trend towards less use of effective contraception among women with a BMI 30-34.9 kg/m² as compared to women with a BMI <30 kg/m².

Conclusion

At 12 months postpartum, obese women were less likely to use effective contraceptive methods than overweight women. Although certain contraceptive methods may be preferred over others in this population, providers should reinforce the importance of effective contraception to avoid unintended pregnancies in obese women.     

Targeted Smoking Cessation Messages for Adolescents

Purpose

To develop and to conduct a preliminary evaluation of smoking cessation messages targeted for adolescents.

Method

We (a) conducted a formative evaluation to identify the optimal content and presentation approach for adolescent-targeted smoking cessation messages, (b) developed two smoking cessation videos catering to adolescent smokers' message preferences, and (c) copy tested the videos to determine the optimal message frame (gain vs. loss) using a quasi-experimental crossover design.

Results

In the formative evaluation, adolescent smokers preferred peer-delivered cessation messages that emphasized long-term health consequences and some social and short-term health consequences of smoking. The information from the formative evaluation was used to create a gain- (emphasized the benefits of quitting and joining a smoking cessation program) and a loss-framed video (emphasized the cost of continuing to smoke and consequences of failing to join a smoking cessation program). The copy test of the videos indicated that adolescents found the messages clear and appealing. The gain-framed message was considered more novel than the loss-framed message and was preferred by most participants. Nonetheless, the loss-framed version resulted in more positive attitudes toward quitting than the gain-framed version.

Conclusion

Little is known about how to construct effective smoking cessation messages tailored specifically for adolescent smokers. The study findings provide insight into adolescents' preferences for message content and presentation. Although considered less novel, providing loss-framed information may be most influential among adolescents. These findings have important implications for developing effective adolescent-targeted smoking cessation messages.     

Cigarette consumption by individuals in Malaysia: a zero-inflated ordered probability approach

Aim

To investigate cigarette consumption patterns exhibited by non-smokers, occasional smokers, and daily smokers in Malaysia.

Subjects and methods

A sample of 4204 individuals from the 2011 Malaysian Global Adult Tobacco Survey is analyzed. A zero-inflated ordered probit model is used to accommodate the ordinal nature of smoking outcomes with excessive zero observations of non-smokers.

Results

Socio-demographic characteristics are closely associated with consumption patterns of non-smokers, occasional smokers, and daily smokers. Specifically, urbanites, government employees, and Malays exhibit greater tendencies to be daily smokers and lower propensities to be non-smokers than others. Education is a deterring factor in cigarette smoking as higher education up to the tertiary level raises the propensity of being a non-smoker by 8.16 percentage points. The role of ethnicity is highlighted as individuals of Malay and other ethnic backgrounds are more likely to smoke daily, while exhibiting lower propensities of being non-smokers. Males are more likely to engage in occasional or daily smoking than females. Employment in government or non-government sectors increases the probability of daily smoking.

Conclusions

Our results suggest the need to include measures to cope with internal or external cues among smokers with specific socio-demographic characteristics. Cessation interventions should focus on daily smokers in urban surroundings with low education levels and those of Malay ethnic origins. Anti-smoking measures in line with occasional smoking may include ameliorating the male attitude toward smoking and policies to prohibit workplace indulgence.

     

Relationship of Ghrelin and Leptin Hormones with Body Mass Index and Waist Circumference in a Random Sample of Adults

Objective

To evaluate the relationship of ghrelin and leptin hormones with body mass index (BMI) and waist circumference in a population-based random sample of adult men and women subsequently categorized from normal weight to severely obese based on BMI criteria. The relationship between total ghrelin and leptin was also evaluated.

Design

A cross-sectional study was conducted on adults.

Methods

Two-hundred thirty-three men (n=107) and women (n=126) between the ages of 23 and 75 years were randomly selected from a database of over 600,000 adults who had previously participated in a population-based study conducted by the University of Utah Cardiovascular Genetics Program. Items collected included height, weight, waist circumference, and fasting blood samples. Blood samples were later thawed, and plasma leptin and total ghrelin levels were analyzed with radioimmunoassay kits.

Results

Leptin levels were directly associated with BMI (r=0.72, P=0.001) and waist circumference (r=0.71, P=0.0001), whereas total ghrelin was inversely associated with BMI (r=−0.39, P=0.001) and waist circumference (r=−0.37, P=0.001). There were also statistically significant linear changes in means across the BMI categories for both hormones. After controlling for BMI and waist circumference, the highly significant correlation of leptin with ghrelin (r=−0.39) was reduced but still significant (r=−0.17, P=0.01).

Conclusion

Leptin increases and ghrelin decreases were linear over the five BMI categories, suggesting there is no threshold of BMI where the hormone levels change abruptly. There remain other factors beyond current BMI and waist circumference that induce a correlation of these two hormones. Further understanding of the role that each of these hormones has in influencing appetite and body weight may provide insight into mechanisms involved with obesity.