Improving mental health in black men through a 24-week community-based lifestyle change intervention: the black impact program

BACKGROUND

Poor mental health is a leading cause of morbidity and mortality among Black men in the United States. Efforts to improve mental health among Black men have been hampered by a lack of access and utilization of mental health services. Physical activity and social networks have been shown to improve mental health. Thus, we examined the effect of a community team-based physical activity, health education and social needs intervention among Black men on mental health over 24 weeks.

METHODS

Black adult males (n = 74) from a large Midwestern city participated in Black Impact, a 24-week community-based lifestyle change program adapted from the Diabetes Prevention Program and American Heart Association's (AHA) Check, Change, Control Blood Pressure Self-Management Program, which incorporates AHA's Life's Simple 7 (LS7) framework. Measures of mental health including the Center for Epidemiological Studies Depression Scale (CES-D), Patient Health Questionnaire 2-question depression screener (PHQ-2), and Perceived Stress Scale-10 (PSS-10) were completed at baseline, 12 and 24 weeks. The change in mental health scores from baseline to 12 and 24 weeks were evaluated using linear mixed-effects models adjusting for age, education, and income. The change in cardiovascular health scores, defined as objective metrics of LS7 (LS5 [blood pressure, total cholesterol, fasting glucose, body mass index and smoking]), by baseline mental health were evaluated using linear mixed-effects models with an interaction term (time*baseline mental health variable) and a random intercept for each participant.

RESULTS

Among 71 Black men (mean age 51, 85% employed) at 24 weeks, CES-D scores decreased from 10.54 to 7.90 (-2.64, 95%CI:-4.74, -0.55), PHQ-2 decreased from 1.04 to 0.63 (-0.41, 95%CI: -0.75, -0.07), and PSS-10 decreased from 14.62 to 12.91 (-1.71, 95%CI: -3.53, 0.12). A 1-unit higher CES-D at baseline was associated with less improvement in LS5 scores by -0.04 (95%CI: -0.076, -0.005) and - 0.032 (95%CI:-0.067, 0.003) units at week 12 and 24, respectively, with similar findings for PSS.

CONCLUSIONS

The Black Impact community-based lifestyle program has the potential to reduce depressive symptoms and stress in Black men. There is a dire need for larger, randomized studies to test the impact of Black Impact on mental health in Black men to advance health equity.

TRIAL REGISTRATION

Retrospectively Registered, ClinicalTrials.gov Identifier: NCT04787978.

Adiposity, aldosterone and plasma renin activity among African Americans: The Jackson Heart Study

Objective

To analyze associations between adiposity and the renin-angiotensin-aldosterone system (RAAS) in a large African American (AA) cohort.

Methods

Cross-sectional associations of adiposity (body mass index [BMI], waist circumference [WC], waist:height ratio, waist:hip ratio, leptin, adiponectin, leptin:adiponectin ratio [LAR], subcutaneous [SAT] and visceral adipose tissue [VAT], and liver attenuation [LA]) with aldosterone, plasma renin activity (renin), and aldosterone:renin ratio (ARR) were assessed in the Jackson Heart Study using adjusted linear regression models.

Results

A 1-SD higher BMI was associated with a 4.8 % higher aldosterone, 9.4 % higher renin, and 5.0 % lower ARR (all p < 0.05). Log-leptin had the largest magnitude of association with renin (30.2 % higher) and ARR (9.6 % lower), while the strongest association of aldosterone existed for log-LAR (15.3 % higher) (all 1-SD, p < 0.05). SAT was only associated with renin. VAT was associated with higher aldosterone, renin, and ARR. Liver fat was associated with aldosterone and renin, but not ARR. Associations of WC, BMI, and SAT with aldosterone were greater in men while the association with VAT was greater in women (p-interactions < 0.05).

Conclusion

Multiple measures of adiposity are associated with the RAAS in AAs. Further studies should examine the role of RAAS in obesity-driven cardiometabolic diseases.

The association of aldosterone and endothelin-1 with incident diabetes among African Americans: The Jackson Heart Study

Introduction

African Americans (AAs) have the highest prevalence of hypertension among United States racial/ethnic groups. Regulators of blood pressure, such as aldosterone and endothelin-1, impact glucose regulation. The relationship between these factors and incident diabetes is not well elucidated among AAs.

Methods

Among 3914 AA participants without prevalent diabetes in the Jackson Heart Study, linear regression models were used to examine cross-sectional associations of exposures (aldosterone, endothelin-1, and a combined aldosterone-endothelin-1 score [2-8]) with glycemic measures (fasting plasma glucose [FPG], HbA1c, homeostatic model assessments of beta cell function [HOMA-β] and insulin resistance [HOMA-IR]). Longitudinal associations of exposures with incident diabetes were examined using Cox proportional hazard models. Models were adjusted for age, sex, education, occupation, systolic blood pressure, smoking, physical activity, dietary intake, alcohol use and adiponectin.

Results

Aldosterone and the combined aldosterone-endothelin score were positively associated with FPG, HOMA-IR, and HOMA-β (all p < 0.05). Endothelin-1 was negatively associated with FPG but positively associated with HOMA-β (both p < 0.05). Only the aldosterone-endothelin score was positively associated with HbA1c (p < 0.01). A 1-SD higher serum aldosterone and endothelin-1 was associated with a 22 % and 14 % higher risk of incident diabetes, respectively, while a 1-point higher aldosterone-endothelin score was associated with a 13 % higher risk of incident diabetes after adjustment for diabetes risk factors (all p < 0.01).

Conclusions

Aldosterone and endothelin-1, factors integral in blood pressure regulation, may play a significant role in the development of diabetes among AAs.

Effects of Hypocaloric Low-Fat, Ketogenic, and Ketogenic and Ketone Supplement Diets on Aldosterone and Renin

CONTEXT

Ketogenic diets (KDs) and low-fat diets (LFD) result in similar weight loss, but have differential cardiometabolic effects on lipids and insulin. Generally, weight loss decreases renin-angiotensin-aldosterone system (RAAS) activity.

OBJECTIVE

Investigate the effects of KDs with varying sodium content vs LFD on RAAS in overweight and obese adults.

METHODS

Twenty-eight participants were randomized 1:1 to a KD + ketone salt supplement (KD + KS) or a KD + placebo (KD + PL) arm with prepared hypocaloric meals. Twelve participants were enrolled in a post hoc LFD arm. Serum renin, aldosterone, and anthropometric and metabolic biomarkers were assessed at 0, 2, 4, and 6 weeks. Linear mixed models with random intercepts were used to compare between group differences controlling for sex and body mass index.

RESULTS

Participants had a median age of 33 years, 51% female, weighed 91.3 kg, with body mass index 30.6 kg/m2. At 6 weeks, weight decreased by 6, 8, and 7 kg on average in the KD + KS, KD + PL, and LFD groups, respectively (P < .05). Aldosterone increased by 88% and 144% in the KD + PL and KD + KS groups, respectively, but did not change in the LFD after 6 weeks while renin decreased across groups. Systolic and diastolic blood pressure did not change in the KD + PL and KD + KS groups. Log ketones were positively associated with aldosterone (P < .001). Aldosterone was not associated with cardiovascular measures including blood pressure and ejection fraction (P > .05).

CONCLUSION

KD reduced weight and increased aldosterone without worsening cardiometabolic risk factors. Future KD studies are needed to elucidate mechanistic connections between ketones and aldosterone.

The Role of Aldosterone and Ideal Cardiovascular Health in Incident Cardiovascular Disease: The Jackson Heart Study

Background

Higher levels of ideal cardiovascular health (ICH) are associated with lower levels of aldosterone and incidence of cardiovascular disease (CVD). However, the degree to which aldosterone mediates the association between ICH and CVD incidence has not been explored. Thus, we investigated the mediational role of aldosterone in the association of 5 components of ICH (cholesterol, body mass index (BMI), physical activity, diet and smoking) with incident CVD and the mediational role of blood pressure (BP) and glucose in the association of aldosterone with incident CVD in a cohort of African Americans (AA).

Methods

The Jackson Heart Study is a prospective cohort of AAs adults with data on CVD outcomes. Aldosterone, ICH metrics and baseline characteristics were collected at exam 1 (2000-2004). ICH score was developed by summing 5 ICH metrics (smoking, dietary intake, physical activity, BMI, and total cholesterol) and grouped into two categories (0-2 and ≥3 metrics). Incident CVD was defined as stroke, coronary heart disease, or heart failure. Cox proportional hazard regression models were used to model the association of categorical ICH score with incident CVD. The R Package Mediation was utilized to examine: 1) The mediational role of aldosterone in the association of ICH with incident CVD and 2) The mediational role of blood pressure and glucose in the association of aldosterone with incident CVD.

Results

Among 3,274 individuals (mean age: 54±12.4 years, 65% female), there were 368 cases of incident CVD over a median of 12.7 years. The risk of incident CVD was 46% lower (HR: 0.54; 95%CI 0.36, 0.80) in those with ≥3 ICH metrics at baseline compared to 0-2. Aldosterone mediated 5.4% (p = 0.006) of the effect of ICH on incident CVD. A 1-unit increase in log-aldosterone was associated with a 38% higher risk of incident CVD (HR 1.38, 95%CI: 1.19, 1.61) with BP and glucose mediating 25.6% (p<0.001) and 4.8% (p = 0.048), respectively.

Conclusion

Aldosterone partially mediates the association of ICH with incident CVD and both blood pressure and glucose partially mediate the association of aldosterone with incident CVD, emphasizing the potential importance of aldosterone and ICH in risk of CVD among AAs.

Cortisol and cardiometabolic disease: a target for advancing health equity

Stress, in both intrinsic psychosocial and extrinsic physical environmental forms, can impact the development of, and outcomes in, cardiovascular disease (CVD) through allostatic load. Cortisol is a core hormonal mediator of allostatic load produced in response to various stresses. Alterations in morning serum cortisol and daily diurnal cortisol have been associated with adiposity, dyslipidemia, incident diabetes, and CVDs such as hypertension. The review examines the role of cortisol as a key mechanistic link between stress physiology and cardiometabolic disease. Importantly, we discuss the role of targeting cortisol through pharmacological, behavioral, and environmental interventions to advance health equity in cardiometabolic disease.

The association of serum vitamin D with incident diabetes in an African American population

BACKGROUND

Incident diabetes risk is inversely proportional to 25-hydroxyvitamin D [25(OH)D] levels among non-Hispanic white but is unclear among African American (AA) populations. Serum 25(OH)D2 may be an important component of total 25(OH)D among AA populations due to higher levels of melanin.

OBJECTIVE

To assess the association of serum 25(OH)D with incident diabetes among AAs and stratify by detectable 25(OH)D2.

DESIGN

Serum 25(OH)D2 and 25(OH)D3 were collected from 2000 to 2004 among AA participants in the Jackson Heart Study. A cosinor model was used to adjust for the seasonality of 25(OH)D3; 25(OH)D3 and 25(OH)D2 were combined to ascertain total 25(OH)D. Incident diabetes (fasting glucose ≥126 mg/dl, use of diabetes drugs, or HbA1c ≥6.5%) was assessed over 12 years among adults without diabetes at baseline. Participants with missing baseline covariates or diabetes follow-up were excluded. Hazard ratios (HR) were estimated using Cox modeling, adjusting for age, sex, education, occupation, smoking, physical activity, alcohol use, aldosterone, and body-mass index.

RESULTS

Among 3311 adults (mean age 53.3 years, 63% female) 584 participants developed diabetes over a median of 7.7 years. After adjustment, 25(OH)D ≥20 compared to <12 ng/ml was associated with a HR 0.78 (95% CI: 0.61, 1.00). Among participants with detectable 25(OH)D2 and 25(OH)D3 (n = 1671), 25(OH)D ≥ 20 ng/ml compared to <12 ng/ml was associated with a 35% (HR 0.65, 95% CI: 0.46, 0.91) lower risk of diabetes.

CONCLUSIONS

Higher levels of 25(OH)D may be protective against the development of diabetes among AA individuals, particularly among those with detectable 25(OH)D2 and 25(OH)D3.

Improving Cardiovascular Health in Black Men Through a 24-Week Community-Based Team Lifestyle Change Intervention: The Black Impact Pilot Study

Background

Higher cardiovascular health scores, using American Heart Association's (AHA) Life's Simple 7 (LS7), have been associated with lower risk of cardiovascular disease, type 2 diabetes, cancer, and mortality among all racial/ethnic groups. Nationally, Black men have the lowest levels of LS7. Thus, a study was conducted to evaluate the impact of a community-based team lifestyle change program on LS7 among Black men.

Methods

Black adult males (n = 74) from a large Midwestern city participated in Black Impact, a 24-week community-based team lifestyle change program adapted from the Diabetes Prevention Program and AHA's Check, Change, Control Blood Pressure Self-Management Program, which incorporates AHA's LS7 framework. The change in a LS7 score (range 0–14) from baseline to 12 and 24 weeks was evaluated using a linear mixed-effects model adjusted for age, education, and income.

Results

The mean age of participants was 52 ± 10 years. The men were sociodemographically diverse, with annual income ranging from <$20,000 (7%) to ≥$75,000 (25%). Twenty-five percent were college graduates, 73% had private insurance, and 84% were employed. In fully adjusted models, LS7 score at baseline was 7.12 and increased 0.67 (95%CI: 0.14, 1.20, p = 0.013) and 0.93 (95%CI: 0.40, 1.46, p<0.001) points at 12 and 24 weeks, respectively, compared to baseline. Sensitivity analysis evaluating 5 components (excluding diet and physical activity) and 6 components (excluding diet) also showed significant increases at 12 and 24 weeks (all p<0.01).

Conclusions

The Black Impact lifestyle change single-arm pilot program showed that a community-based lifestyle intervention has the potential to improve LS7 in Black men. Further randomized studies are urgently needed to improve cardiovascular health and advance cardiovascular health equity in Black men.

Association of Adiposity With Incident Diabetes Among Black Adults in the Jackson Heart Study

Background

The prognostic value of anthropometric, adipokine, and computed tomography measures of adiposity to predict diabetes in Black, specifically by normoglycemia versus prediabetes, remains incompletely understood.

Methods and Results

Among Black participants without diabetes in the JHS (Jackson Heart Study), waist circumference [WC], body mass index, adiponectin, leptin, and leptin:adiponectin ratio were standardized in sample 1 (2422 participants at baseline [2000–2004]) and WC, body mass index, visceral adipose tissue (VAT), subcutaneous adipose tissue, and liver attenuation in 1537 participants at examination 2 (2005–2008) (sample 2). Hazard ratios (HRs) for diabetes were estimated using interval‐censored Cox modeling adjusting for traditional risk factors and validated with the C index. Over 5 years, 300 and 122 incident diabetes cases occurred in sample 1 and sample 2, respectively. In sample 1 and sample 2, a 1‐SD higher log‐leptin:adiponectin ratio and VAT had the strongest associations (HR, 1.95 [95% CI, 1.67–2.27] and 1.76 [95% CI, 1.52–2.04]) and discriminatory power (C index 0.68 [95% CI, 0.64–0.71] and C index 0.67 [95% CI, 0.61–0.74]) with diabetes. The normoglycemic compared with the prediabetes group had a 1.3 to 1.9 times greater magnitude of associations with diabetes for WC, liver attenuation, and VAT (P interaction <0.10). In sample 2, C indices for WC (HR, 0.84; 95% CI, 0.73–0.95), VAT (HR, 0.91; 95% CI, 0.85–0.98), and liver attenuation (HR, 0.90; 95% CI, 0.77–1.00) were greater than HbA_1c (HR, 0.74; 95% CI, 0.57–0.90) in normoglycemia, whereas HbA_1c was best in prediabetes (HR, 0.72; 95% CI, 0.66–0.78).

Conclusions

Overall, among Black adults, multiple measures of adiposity were associated with incident diabetes with modest predictive ability. In Black patients with normoglycemia, WC, liver attenuation, and VAT may appropriately identify those at high risk for diabetes, whereas HbA_1c was the best predictor in individuals with prediabetes.

Association of Serum Aldosterone and Plasma Renin Activity With Ambulatory Blood Pressure in African Americans: The Jackson Heart Study

BACKGROUND

The renin-angiotensin-aldosterone system (RAAS) is an important driver of blood pressure (BP), but the association of the RAAS with ambulatory BP (ABP) and ABP monitoring phenotypes among African Americans has not been assessed.

METHODS

ABP and ABP monitoring phenotypes were assessed in 912 Jackson Heart Study participants with aldosterone and plasma renin activity (PRA). Multivariable linear and logistic regression analyses were used to analyze the association of aldosterone and PRA with clinic, awake, and asleep systolic BP and diastolic BP (DBP) and ABP monitoring phenotypes, adjusting for important confounders.

RESULTS

The mean age of participants was 59±11 years and 69% were female. In fully adjusted models, lower log-PRA was associated with higher clinic, awake, and asleep systolic BP and DBP (all P<0.05). A higher log-aldosterone was associated with higher clinic, awake, and asleep DBP (all P<0.05). A 1-unit higher log-PRA was associated with lower odds of daytime hypertension (odds ratio [OR] 0.59 [95% CI, 0.49-0.71]), nocturnal hypertension (OR, 0.68 [95% CI, 0.58-0.79]), daytime and nocturnal hypertension (OR, 0.59 [95% CI, 0.48-0.71]), sustained hypertension (OR, 0.52 [95% CI, 0.39-0.70]), and masked hypertension (OR 0.75 [95% CI, 0.62-0.90]). A 1-unit higher log-aldosterone was associated with higher odds of nocturnal hypertension (OR, 1.38 [95% CI, 1.05-1.81]). Neither PRA nor aldosterone was associated with percent dipping, nondipping BP pattern, or white-coat hypertension. Patterns for aldosterone:renin ratio were similar to patterns for PRA.

CONCLUSIONS

Suppressed renin activity and higher aldosterone:renin ratios were associated with higher systolic BP and DBP in the office and during the awake and asleep periods as evidenced by ABP monitoring. Higher aldosterone levels were associated with higher DBP, but not systolic BP, in the clinic and during the awake and asleep periods. Further clinical investigation of novel and approved medications that target low renin physiology such as epithelial sodium channel inhibitors and mineralocorticoid receptor antagonists may be paramount in improving hypertension control in African Americans.

Adiposity Measures and Morning Serum Cortisol in African Americans: Jackson Heart Study

OBJECTIVE

Altered hormonal regulation, including cortisol, is a proposed mechanism linking adiposity to obesity-related disorders. We examined the association of anthropometric, adipokine, and body fat distribution measures of adiposity with morning serum cortisol in an African American (AA) cohort.

METHODS

We investigated the cross-sectional associations of adiposity measures (BMI, waist circumference, leptin, adiponectin, leptin:adiponectin ratio, subcutaneous and visceral adipose tissue) and liver attenuation with cortisol in the Jackson Heart Study. Linear regression models were used to analyze the association between exposures and cortisol. Models were adjusted for multiple covariates.

RESULTS

Among 4,211 participants, a 1-SD higher BMI and waist circumference were associated with a 3.92% and 3.05% lower cortisol, respectively. A 1-SD higher leptin and leptin:adiponectin ratio were associated with a 6.48% and 4.97% lower morning serum cortisol, respectively. A 1-SD higher subcutaneous adipose tissue was associated with a 4.97% lower cortisol (all P < 0.001). There were no associations of liver attenuation or visceral adipose tissue with cortisol.

CONCLUSIONS

Several measures of adiposity are associated with lower morning serum cortisol among AAs, with leptin having the greatest magnitude. Future studies examining the role of morning serum cortisol in the pathway from adiposity to cardiometabolic disease in AAs are warranted.

The association of cortisol curve features with incident diabetes among whites and African Americans: The CARDIA study

INTRODUCTION

A flatter diurnal cortisol curve has been associated with incident diabetes among older white adults. However, this relationship has not been examined among middle-aged individuals or African Americans [AA]. We analyzed the longitudinal association of baseline diurnal cortisol curve features with incident diabetes over a 10 year period in a cohort of AA and white participants who were, on average, 40 years old.

METHODS

Salivary cortisol was collected immediately post-awakening, then subsequently 45 min, 2.5 h, 8 h, and 12 h later, as well as at bedtime. Cortisol curve features included wake-up cortisol; cortisol awakening response (CAR); early, late, and overall decline slopes; bedtime cortisol; and 16 -h area under the curve (AUC). Salivary cortisol (nmol/L) was log-transformed due to positively skewed distributions. Diabetes was defined as fasting plasma glucose ≥ 126 mg/dL or taking diabetes medication. Logistic regression models were used to investigate the association of log-transformed cortisol curve features with incident diabetes. The analysis was stratified by race and adjusted for age, sex, education, depressive symptoms, smoking status, beta-blocker and steroid medication use and BMI.

RESULTS

Among 376 AA and 333 white participants (mean age 40 years), 67 incident diabetes cases occurred over 10 years. After full adjustment for additional covariates, a 1-unit log increase in CAR was associated with a 53 % lower odds of incident diabetes among whites (Odds Ratio [OR] 0.47, 95 % CI: 0.24, 0.90). A 1-SD increase in late decline slope was associated with a 416 % higher odds of incident diabetes among whites (OR 5.16, 95 % CI: 1.32, 20.20). There were no significant associations in AAs.

CONCLUSION

A robust CAR and flatter late decline slope are associated with lower and higher odds of incident diabetes, respectively, among younger to middle-aged whites and may provide a future target for diabetes prevention in this population.

The longitudinal association of changes in diurnal cortisol features with fasting glucose: MESA

Little is known about the longitudinal association between fasting glucose (FG) and the diurnal cortisol profile among those with normal fasting glucose (NFG), impaired fasting glucose (IFG) and diabetes. To assess the temporality of the relationship between cortisol and glucose, we examined the association of: A) change (Δ) in diurnal cortisol curve features with ΔFG; B) prior annual percent change in FG with diurnal cortisol curve features; and C) baseline cortisol curve features with ΔFG over 6 years among participants with NFG, IFG and diabetes in the Multi-Ethnic Study of Atherosclerosis. The main outcome measures were: A) 6-year ΔFG (n = 512); B) diurnal cortisol curve features (wake-up cortisol levels, cortisol awakening response, total area under the curve, overall decline slope and bedtime cortisol) (n = 1275); and C) 6-year ΔFG (n = 700). After full multivariable adjustment among participants with diabetes, each annual percent change increase in wake-up cortisol, total area under the curve (AUC), and overall decline slope was associated with a significant increase in FG over 6 years in all models (all p < 0.05). A 1% prior annual increase in FG was associated with a 2.8 % lower (-2.8 %; 95 % CI: -5.3 % to -0.4 %) bedtime cortisol among participants with NFG at baseline. A 1 % flatter overall decline slope was associated with a 0.19 % increase in subsequent annual % change in FG over 6 years among participants with diabetes. Among participants with diabetes there was a positive association of change in wake-up cortisol, total AUC and overall decline slope with change in FG. Baseline overall decline slope was positively associated with change in FG among the baseline diabetes group. These results suggest a detrimental role of cortisol contributing to glycemia among individuals with diabetes.

Infrared thermography and ulcer prevention in the high-risk diabetic foot: data from a single-blind multicentre controlled clinical trial

AIM

To assess the usefulness of monthly thermography and standard foot care to reduce diabetic foot ulcer recurrence.

METHODS

People with diabetes (n = 110), neuropathy and history of ≥ 1 foot ulcer participated in a single-blind multicentre clinical trial. Feet were imaged with a novel thermal imaging device (Diabetic Foot Ulcer Prevention System). Participants were randomized to intervention (active thermography + standard foot care) or control (blinded thermography + standard foot care) and were followed up monthly until ulcer recurrence or for 12 months. Foot thermograms of participants from the intervention group were assessed for hot spots (areas with temperature ≥ 2.2°C higher than the corresponding contralateral site) and acted upon as per local standards.

RESULTS

After 12 months, 62% of participants were ulcer-free in the intervention group and 56% in the control group. The odds ratios of ulcer recurrence (intervention vs control) were 0.82 (95% CI 0.38, 1.8; P = 0.62) and 0.55 (95% CI 0.21, 1.4; P = 0.22) in univariate and multivariate logistic regression analyses, respectively. The hazard ratios for the time to ulcer recurrence (intervention vs control) were 0.84 (95% CI 0.45, 1.6; P = 0.58) and 0.67 (95% CI 0.34, 1.3; P = 0.24) in univariate and multivariate Cox regression analyses, respectively.

CONCLUSIONS

Monthly intervention with thermal imaging did not result in a significant reduction in ulcer recurrence rate or increased ulcer-free survival in this cohort at high risk of foot ulcers. This trial has, however, informed the design of a refined study with longer follow-up and group stratification, further aiming to assess the efficacy of thermography to reduce ulcer recurrence.

Reliability of a novel thermal imaging system for temperature assessment of healthy feet

Background

Thermal imaging is a useful modality for identifying preulcerative lesions (“hot spots”) in diabetic foot patients. Despite its recognised potential, at present, there is no readily available instrument for routine podiatric assessment of patients at risk. To address this need, a novel thermal imaging system was recently developed. This paper reports the reliability of this device for temperature assessment of healthy feet.

Methods

Plantar skin foot temperatures were measured with the novel thermal imaging device (Diabetic Foot Ulcer Prevention System (DFUPS), constructed by Photometrix Imaging Ltd) and also with a hand-held infrared spot thermometer (Thermofocus® 01500A3, Tecnimed, Italy) after 20 min of barefoot resting with legs supported and extended in 105 subjects (52 males and 53 females; age range 18 to 69 years) as part of a multicentre clinical trial. The temperature differences between the right and left foot at five regions of interest (ROIs), including 1st and 4th toes, 1st, 3rd and 5th metatarsal heads were calculated. The intra-instrument agreement (three repeated measures) and the inter-instrument agreement (hand-held thermometer and thermal imaging device) were quantified using intra-class correlation coefficients (ICCs) and the 95% confidence intervals (CI).

Results

Both devices showed almost perfect agreement in replication by instrument. The intra-instrument ICCs for the thermal imaging device at all five ROIs ranged from 0.95 to 0.97 and the intra-instrument ICCs for the hand-held-thermometer ranged from 0.94 to 0.97. There was substantial to perfect inter-instrument agreement between the hand-held thermometer and the thermal imaging device and the ICCs at all five ROIs ranged between 0.94 and 0.97.

Conclusions

This study reports the performance of a novel thermal imaging device in the assessment of foot temperatures in healthy volunteers in comparison with a hand-held infrared thermometer. The newly developed thermal imaging device showed very good agreement in repeated temperature assessments at defined ROIs as well as substantial to perfect agreement in temperature assessment with the hand-held infrared thermometer. In addition to the reported non-inferior performance in temperature assessment, the thermal imaging device holds the potential to provide an instantaneous thermal image of all sites of the feet (plantar, dorsal, lateral and medial views).

Trial registration

Diabetic Foot Ulcer Prevention System NCT02317835, registered December 10, 2014