Comparative Evaluation of Three Cranberry Formulations in Women with Recurrent Urinary Tract Infections: An Observational Study

Abstract

Purpose

Although cranberry supplementation has been investigated for recurrent UTI prevention with heterogeneous demonstrations, direct comparisons of putative active compositions remain scarce. The present study aimed to compare three cranberry formulations differing in composition and PACs (Proanthocyanidins) profiles on recurrent UTI episodes, urinary symptoms and quality of life in women with recurrent UTIs.

Patients and Methods

Three extracts differing in the sources of their fruits, extraction process, solubility, and composition were characterized (40SD, 40G, and FG). A total of 219 women aged 18 to 65 years with recurrent UTI episodes were enrolled in an observational, comparative, open-label, parallel clinical study and allocated to receive one of three treatments for 6 months. Posology was standardized to provide equivalent amounts of PACs, and endpoints were assessed at baseline and after 6 months.

Results

Extract characterization differed notably for organic acids, fibre, monomeric phenolic compounds, soluble and oligomeric forms of PACs, and the degree of polymerization. All three extracts significantly improved urinary comfort (VAS, 53.8 ± 16.2 → 80.9 ± 25.6; p < 0.001), symptomatic episodes (frequency: 2.9 → 0.8; p < 0.001; duration: 2.7 → 0.7 days; p < 0.001), global symptom intensity assessed using the ACSS, global quality of life assessed using the SF-Qualiveen, and psychosocial impact questionnaire scores, with no significant differences between groups. However, the 40G group showed a significantly greater improvement in ACSS-Differential scores (symptoms related to adjacent organs) during cystitis-like episodes, complementary ACSS items (eg, burden on daily activities), the “Fears” domain of SF-Qualiveen, and earlier onset of significant effects in these questionnaires.

Conclusion

The standardization of posology based on total PACs (162 mg/day, including insoluble polymeric forms) rather than soluble oligomeric PACs (36 mg/day, BL-DMAC) appears relevant for the improvement of UTIs and related symptoms. Treatment with an extract (40G) with a specific ratio of insoluble/soluble fruit parts and, consequently, a distinct PACs profile resulted in greater improvements.

Trial Registration

NCT04962971.

Background

Among urinary symptoms, the urgent need to urinate, increased urinary frequency, pain, and a burning sensation during urination (dysuria) are the most prevalent and predictive symptoms reported in urinary tract infection (UTI).1 Lower urinary tract infection, the most common type of UTI, is often described as cystitis, which is related to bladder inflammation and associated symptoms. No other medical condition requires as many medical consultations, bacteriological examinations, or antibiotic prescriptions as cystitis.2 In the United States, the lifetime incidence of UTIs exceeds 50% in women.3

Here, we considered community-acquired UTIs (as opposed to health care-associated UTIs). According to a large survey of women, 10.8% reported at least one presumed UTI during the previous 12 months.4 Following a first UTI episode, 27% of women experienced a confirmed recurrence within the subsequent 6 months.5–8 Among self-diagnosed UTIs based on presumptive symptoms reported by young women with recurrent episodes, 84% were confirmed by the presence of uropathogenic bacteriuria.9 This high confirmation rate highlights the relevance of self-reported symptoms for UTI detection in women with recurrent infections.

The causative strains most frequently isolated from urine are Escherichia coli, followed by Klebsiella pneumoniae and other species, all of which have developed increasing antibiotic resistance over time and require regular and extensive antimicrobial susceptibility testing to adjust treatment strategies.10–13 In this context, the use of nonantibiotic prophylactic approaches has become a major public health issue.14 Cranberry fruit (Vaccinium macrocarpon) supplementation has traditionally been used for the relief and prevention of symptoms associated with recurrent lower UTIs.15–20 This claim has been extensively investigated in clinical trials, and several meta-analyses have concluded that cranberry intake may significantly reduce the incidence of UTIs in susceptible populations. However, the results remain inconsistent because of the heterogeneous study designs and inequivalent quality and quantity of the cranberry products tested.16–20 In 2020, the US Food and Drug Administration (FDA) published a qualified health claim related to the reduction of recurrent UTIs for only two cranberry products (cranberry juice beverage and whole-fruit powder, without compositional clarification).21 Despite this recognition of the health benefits of cranberry, the FDA has reported limited and inconsistent scientific evidence.

Several categories of cranberry-derived compounds have been proposed to contribute to the inhibition of uropathogenic strains in vivo. The earliest described active compounds were organic acids, which were initially proposed to act as urine acidifiers and have been investigated for their potential activity, with significant effects reported in several studies.22,23 Specific polysaccharides, such as arabinoxyloglucan oligosaccharides and pectic oligosaccharides, have more recently been identified as contributors to uropathogen inhibition in the context of UTIs.24,25 The most extensively studied active compounds are proanthocyanidins (PACs) with A-type linkages because of their ability to bind proteins, particularly bacterial adhesins, thereby preventing bacterial adhesion to the epithelium in the urinary tract wall.26–28 In 2004, the French Agency for Food Safety (AFSSA) recognized the antiadhesive activity against E. coli in the urinary tract of several cranberry products characterized as providing 36 mg/day of PACs quantified using the DMAC method. Although in 2010, 2011, and 2022, the French Agency for Food, Environmental and Occupational Health and Safety (ANSES, formerly AFSSA), the European Food Safety Authority (EFSA), and the European Medicines Agency (EMA), respectively, published assessment reports highlighting insufficient scientific evidence to support a clear beneficial effect of cranberry intake on UTIs in women, the 36 mg/day PACs dosage has nevertheless been widely considered a reference standard across many proposed dosages.29–31 PACs quantification remains challenging, as the reported concentrations may vary up to a fivefold difference depending on the analytical method used and up to a threefold difference depending on the reference standard. Among the available methods, such as DMAC, butanolysis (adapted from Bate-Smith), the Folin assay, and chromatographic separation by HPLC, the US Pharmacopeia stated in its 2021 monograph on cranberry extract that DMAC is a suitable method for quantifying PACs specifically in soluble cranberry fractions (ie, fruit juice-based products).32 For insoluble PACs, which are characterized by a relatively high degree of polymerization, butanolysis has been proposed as a suitable method for quantifying total PACs in products containing insoluble cranberry fractions (ie, from fruit pomace).33 Based on reports from the EMA, FDA, ANSES, EFSA, and the aforementioned meta-analyses, a persistent lack of consistency in scientific evidence has been highlighted. Differences in cranberry extract compositions have been proposed as a major factor explaining the divergent conclusions across clinical studies.

Although cranberry products have been extensively investigated in women with recurrent UTIs, there are discrepancy in observed benefits due to heterogenous product and posology investigations and direct head-to-head comparisons between formulations with markedly different putative actives PACs compositions remain limited. Therefore, the present study aimed to compare three cranberry formulations, one of which proposed as a reference providing 36mg of PACs quantified by (BL-)DMAC methodology, while evaluating urinary symptoms, recurrence characteristics and quality of life. To our knowledge, this study is the first clinical study combining a direct comparison of three cranberry formulations with a detailed compositional characterization of PACs profiles and other putative active compounds.

Methods

Study Aim, Design, and Settings

This prospective, observational, open-label, parallel-group comparative study was conducted to compare the clinical effects of three cranberry formulations standardized to an equivalent total PACs content (162 mg of total PACs/day). All participants received comprehensive written information about this study and provided informed consent.

The exclusion criteria were current or planned pregnancy within the next six months, breastfeeding, intake of any other food supplements for urinary discomfort or cranberry-based products within the past three months, ongoing symptomatic urinary episodes or antibiotic treatment at enrolment, and allergy to cranberries or related species to reflect the real-life conditions of use.

Characteristics of the Participants

Women aged 18 to 65 years were eligible for inclusion if they had experienced at least three symptomatic episodes of cystitis during the past 12 months, with at least one episode confirmed by a physician, and reported an impaired quality of life, rated >2 on the quality of life (QoL) domain of the self-administered Acute Cystitis Symptom Score (ACSS).34

Once enrolled, the investigators collected baseline data and provided a six-month supply of one of the three cranberry extracts, depending on the group to which the participant was allocated. During follow-up, participants reported outcomes at predefined intervals and, if a symptomatic episode occurred, using the secure e-PRO NursTrial^® app.

Characterisation of Cranberry Formulations

(BL-)DMAC methodology mainly quantified soluble PACs with relatively low degree of polymerisation. Quantification of total PACs containing soluble and insoluble PACs was performed using butanolysis methodology (Bate-Smith). Insoluble PACs are mainly composed by high degree of polymerisation linked to protein and fibres. Chromatographic methodology (UHPLC-DAD-MS) allowed identification and quantification of phenolic compound including anthocyanins, and with a degree of polymerisation up to 4. Phloroglucinolysis methodology assessed mean degree of polymerisation and proportion of A type linkages. Organic acids were quantified using standard HPLC methodology. Detailed methodologies are based on previously published analytical methods.35–40 and are described in Supplementary Data.

Cranberry Formulations

Exocyan™ Cran 40SD (40SD) contains cranberry juice and purified juice (purification through an adsorbent resin column that allows PACs concentration), Exocyan™ Cran 40G (40G) is a mixture of purified juice and pomace, and Exocyan™ FG (FG) is a mixture of juice and pomace with a relatively high proportion of pomace. All extracts were provided by Nexira, France. The detailed composition is presented in Table 1. In this study, the daily dosage of each of the 3 cranberry extracts (Vaccinium macrocarpon Aiton) was adjusted to provide 162 mg/day of total PACs assessed using the butanolysis method, specifically corresponding to 36 mg of PACs assessed using the (BL-)DMAC method for 40SD and finally corresponding to 373 mg/day of 40SD, 404 mg/day of 40G (both as single capsules) and 2090 mg/day of FG (provided as 5 capsules of 418 mg).

Table 1.

Composition of Cranberry Extracts and Related Daily Intake of the Compounds

	40SD (373 mg/day)		40G (404 mg/day)		FG (2090 mg/day)
	Content (g/100 g)	Intake (mg/day)	Content (g/100 g)	Intake (mg/day)	Content (g/100 g)	Intake (mg/day)
Nutritional composition
Humidity	4.5	18.0	4.4	16.5	4.5	94.7
Minerals	6.0	24.2	0.7	2.7	4.8	100.3
Sugar	22.2	89.7	6.7	25.0	23.1	482.8
Lipids	0.4	1.6	3.7	13.8	2.8	58.5
Proteins	0.7	2.7	4.8	17.9	3.3	69.0
Fibre	9.7	39.2	47.7	177.9	42.8	894.5
Organic acids (HPLC)
Quinic acid	7.1	28.6	1.3	4.8	6.2	129.8
Citric acid	6.9	27.8	1.5	5.7	6.2	128.5
Malic acid	5.0	20.3	1.0	3.6	4.6	95.9
Total organic acids	19.0	76.7	3.8	14.1	17.0	354.3
PACs
Total PACs (Bate-Smith eq. B2)	40.1	162.2	43.4	161.9	7.8	162.0
PACs ((BL-)DMAC eq. B2)	9.0	36.5	6.5	24.4	0.8	15.9
Degree of polymerization (DPm)	3.7		4.4		5.3
Proportion of A-type linkages (relative %)	15.6		13.9		9.1
Profile of polyphenols (UHPLC-MS)
Phenolic acids (chlorogenic acid, caffeic acid, coumaric acid, and derivatives)	1.02	4.1	0.82	3.1	0.07	1.5
Flavonols (quercetin, myricetin and derivatives)	2.08	8.4	1.73	6.5	0.14	2.8
Anthocyanins (cyanidin glycoside and peonidin glycoside)	0.90	3.6	0.75	2.8	0.07	1.5
Proanthocyanidins
Monomer (epicatechin)	0.24	1.0	0.19	0.7	0.02	0.4
PACs—B-type dimers	0.22	0.9	0.20	0.7	0.01	0.2
PACs—A2 dimer	0.55	2.2	0.45	1.7	0.04	0.8
PACs—A-type trimers	0.74	3.0	0.61	2.3	0.05	1.1
PACs—A-type tetramers	0.10	0.4	0.09	0.3	0.1	0.1
Total PACs	1.61	6.5	1.35	5.0	0.11	2.2
Proportion of PACs with A-type linkages (based on the PACs profile) (relative %)	86		85		89
Total polyphenols detected using UHPLC	5.85	23.6	4.84	18.0	0.40	8.4

Notes: Bold values: the daily dosage of each of the 3 cranberry extracts (Vaccinium macrocarpon Aiton) was adjusted to provide ≈ 162 mg/day of total PACs.

Primary Outcome

The primary outcomes were changes in urinary comfort ratings determined using an electronic 0–100 visual analogue scale (VAS),41 where 0 indicates no comfort and 100 indicates complete comfort, and in quality of life assessed using the ACSS-QoL domain, which ranges from 0 (no impact on QoL) to 9 (maximum impact on QoL), throughout the study period.

Clinical Data Collection

At baseline, data concerning women’s age, body mass index, symptomatic episodes (total number of episodes with urinary symptoms, notably self-characterized cystitis), episodes with consultation (the subset of symptomatic episodes that led to a physician consultation), cystitis confirmation by a cytobacteriological examination of urine (CBEU) and related antibiotic use during the past 12 months, as well as average the episode duration and ACSS scores, were collected. The ACSS is a questionnaire for clinical diagnosis and patient-reported outcomes in women with acute cystitis.34 ACSS-Total values range from 0 (no urinary symptoms) to 39 (maximum urinary symptoms), the scores for the ACSS-Typical domain ranges from 0 (no symptoms) to 18 (maximum symptom severity), and the scores for the ACSS-Differential domain ranges from 0 (no symptoms) to 12 (maximum symptom severity). An episode was classified as cystitis when both of the following conditions were met: 1) ACSS Q3 ≥1 (burning pain during urination) on the first day and 2) ACSS Q1 ≥1 (frequent urination of small volumes) or Q2 ≥1 (urgency). These criteria were chosen because of their ability to predict urinary tract infection in women.1,8 Episodes not meeting these criteria were classified as cystitis-like.

During the 6-month cranberry supplementation period, women rated their urinary comfort using a VAS and reported their ACSS-QoL every two weeks. They also completed the short form (8 items) of the Qualiveen questionnaire (SF-Qualiveen) and the Psychosocial Impact questionnaire at months 1, 3, and 6.42 Qualiveen is a health-related quality of life questionnaire specific to urinary disorders. SF-Qualiveen consists of 4 domains (“Bothered with limitations”, “Constraints”, “Fears”, and “Feelings”), rated from 0 (Not at all/Always) to 4 (Extremely/Never), where 4 indicates maximal impairment. The Psychosocial Impact questionnaire consists of 11 items rated from –2 (worst) to +2 (best). When a symptomatic episode occurred, women reported its duration, antibiotic use if any, and completed the ACSS each day throughout the episode.

Statistical Analysis

A total of 59 subjects in each group was needed to detect a mean difference of 15 points in the 0–100 VAS of urinary comfort between the two groups, assuming a standard deviation (SD) of 25, with 90% power and α = 0.05, using a paired t test. This number was increased to 216 to account for potential withdrawals.

Descriptive analyses were conducted on subjects with available data (baseline characteristics, VAS score for urinary comfort, ACSS score, SF-Qualiveen score, and Psychosocial Impact questionnaire score). Quantitative variables are presented as the means ± SDs and/or medians with 95% confidence intervals (95% CIs). Qualitative variables are reported as counts and percentages. Differences from the baseline at predefined time points were compared between groups using two-way (time × treatment) ANOVA. Within each group, the baseline and final values obtained after supplementation were compared using paired t tests. Statistical significance was defined as α = 0.05. All analyses were performed using SAS software, version 9.4.

Results

Composition of Cranberry Extracts

The composition of the 3 cranberry extracts is described in Table 1, which provides the equivalent amount of intake per day for each compound. In terms of organic acids, the ratios of quinic acid, citric acid and malic acid were similar (approximately 1:1:1) between the extracts. As organic acid concentrations differ between extracts because of the purification process, the daily intake differed between groups and was 76.7 mg/day for 40SD, 14.1 mg/day for 40G and 354.3 mg/day for FG.

The total PACs (Bate-Smith) daily intake was standardized at 162 mg/day for all groups, but the daily intake of PACs (BL-)DMAC varied from 36.5 mg/day for the 40SD group to 24.4 mg/day for the 40G group and 15.9 mg/day for the FG group. This difference in the ratio of PACs (BL-)DMAC to total PACs (Bate-Smith) is due to the specificity of the analysis and source of the extracts (described above), as the (BL-)DMAC method is driven by soluble PACs (oligomeric forms), whereas the Bate-Smith method considers insoluble PACs (polymeric and complexified forms of PACs). Accordingly, the PACs (BL-)DMAC concentration was negatively correlated with the degree of polymerization of the PACs (3.7 ± 1.1% RSD for 40SD, 4.4 ±1.5% RSD for 40G and 5.3 ± 4.1% RSD for FG).

According to the polyphenolic profile obtained using UHPLC‒MS, the 3 extracts contain phenolic acids and flavonoids, including PACs, anthocyanins and flavanols. As this method detects monomeric and phenolic compounds with a DP of up to 4, the total quantity of polyphenols detected remains lower than the PACs quantity, and the 40SD extract (from juice) had the highest content. The final daily intake was 23.6 mg/day for 40SD, 18.0 mg/day for 40G and 8.4 mg/day for FG. These results indicate a high content of A-type procyanidins (mainly trimeric forms) compared with B-type procyanidins (from 86 to 89%) for all the extracts, and this proportion differed substantially from the proportion of A-type bound linkages assessed using the phloroglucinolysis method (15.6% for 40SD, 13.9% for 40G and 9.1% for FG). The A-type classification of PACs is characterized by at least one A-type linkage between units, but other linkages could be of a B-type nature. These results suggest that A-type PACs are the most abundant in cranberry (especially in oligomeric forms), but the proportion of A-type linkages among total PACs is limited. The proportion of detected moieties after phloroglucinolysis (epicatechin, epigallocatechin and PACs-A2 dimer) did not differ significantly between the extracts.

The quantification of all the PACs remains challenging because of the specificity of the method and PACs solubility and degree of polymerization, but we should mention that the Bate-Smith method seems to be relevant, as the sum of all the classes in terms of nutritional composition and organic acids is closer to the complete characterization, with moderate overestimation (102.6% for 40SD, 115.2% for 40G and 106.0% for FG).

Study Population

A total of 219 women were included in this observational study. The effectiveness analysis set included 202 women who completed the 6-month follow-up with optimal compliance to extract consumption. As shown in Figure 1, women were evenly allocated between groups: 70 in the 40G group, 67 in the 40SD group, and 65 in the FG group.

Figure 1.

Flow chart of the study.

Patient Characteristics at Baseline

The demographic, anthropometric, and episode characteristics of the women are presented in Table 2. The average age of the women was 38.2 ± 10.8 years; 24.3% were older than 45 years. On average, women were norm-weighted in the 40G and FG groups and overweight in the 40SD group, as shown by a small but statistically significant difference in mean BMI (p < 0.01), which was not considered clinically relevant. Over the past 12 months, women experienced a mean of 6.0 symptomatic episodes in the 40SD group and 5.7 episodes in both the 40G and FG groups, with mean episode durations of 5.7, 5.0, and 5.3 days, respectively (no significant difference). Urine culture and bacteriological examination (UCBE) confirmed a diagnosis of cystitis with a frequency close to that of episodes requiring medical consultation. Episodes with consultation were modestly but significantly less frequent in the 40SD group than in the FG group and represented 38% (40SD), 49% (40G), and 56% (FG) of overall symptomatic episodes. All UCBE-confirmed cystitis episodes were treated with antibiotics. Urinary comfort did not differ between groups and was rated 53.8 ± 16.2 on the 0–100 VAS in the overall population, corresponding to mild urinary discomfort. Symptom severity did not differ between groups and was classified as mild to moderate according to the ACSS-Total score of 18.1 ± 5.5 for all women. ACSS-QoL was the most impacted domain, with a mean value representing 69% of the maximal score.

Table 2.

Baseline Women’s Characteristics

	40SD (n=67)		40G (n=70)		FG (n=65)		Significance of Differences Between Groups
	Mean	SD	Mean	SD	Mean	SD
Characteristics of the women
Age (years)	39.5	11.4	36.8	11.0	38.4	9.8	NS
BMI (kg/m2)	26.6a	5.6	24.3b	5.1	23.6b	5.1	P<0.01
Characteristics of the episodes
Symptomatic episodes (number/year)	6.0	5.0	5.7	3.6	5.7	3.2	NS
Episodes with consultation (number/year)	2.5a	1.8	2.8	2.1	3.4b	2.0	P<0.05
Positive UCBE (number/year)	2.3a	1.6	2.8	2.0	3.2b	1.9	P<0.05
Duration of urinary episodes (days/episode)	5.7	4.9	5.0	5.0	5.3	3.6	NS
Antibiotics (number/year)	2.2	1.7	2.7	2.2	3.1	1.9	NS
Perceived comfort (0–100 points on the VAS)	52.9	15.4	53.8	14.2	54.8	19.1	NS
ACSS-Total	17.5	5.0	18.3	5.8	18.7	5.5	NS
ACSS-Typical	9.0	3.2	9.6	3.4	9.6	2.9	NS
ACSS-Differential	2.8	1.8	2.5	2.2	3.1	2.5	NS
ACSS-QoL	5.7	1.9	6.2	2.1	6.0	1.6	NS

Note: ^{a, b} Different letters indicate significant differences between 2 groups (p value <0.05).

Abbreviations: NS, not statistically significant; SD, standard deviation.

Primary Endpoint: Changes in Urinary Comfort and the Impact of Symptomatic Episodes on Quality of Life (ACSS-QoL)

As shown in Figure 2, all the women rapidly reported significant improvement in urinary comfort (p<0.05) compared to the baseline score. After the second week, urinary comfort continued to gradually increase in all groups, with significantly higher VAS scores during the 6 months of supplementation than during W2. No significant difference in the VAS score for urinary comfort was observed between groups throughout the study. At the end of the supplementation period, urinary comfort increased by 25.8 ± 29.8 points in the 40G group (p < 0.0001), 30.9 ± 26.0 points in the 40SD group (p < 0.0001), and 24.6 ± 38.7 points in the FG group (p < 0.001), reaching a mean 0–100 VAS score of 80.9 ± 25.6 in the overall population. This result corresponds to an approximately 50% improvement from baseline and reflects good urinary comfort. Compared with the baseline, after 2 weeks of cranberry product supplementation, ACSS-QoL scores decreased markedly by −5.2 ± 2.7 points in the 40G group (p < 0.0001), −4.4 ± 2.7 points in the 40SD group (p < 0.0001), and −5.1 ± 2.5 points in the FG group (p < 0.0001). After 6 months, the decrease in ACSS-QoL reached −5.5 ± 2.4 points in the 40G group, −5.1 ± 2.3 points in the 40SD group, and −5.2 ± 2.5 points in the FG group (all p < 0.0001). After 6 months, the ACSS-QoL values remained below 1 point (of a maximum of 9 points) in all groups, confirming a sustained improvement in the quality-of-life domain.

Figure 2.

Effect of daily consumption of cranberry extracts (40SD, 40G and FG) over 24 weeks on urinary comfort evaluated by a VAS score ranging from 0 to 100 points (0: no comfort; 100: total comfort). * Indicates a significant difference (p<0.05) in the VAS score between the baseline and W24. $ indicates a significant difference (p<0.05) in the VAS score between W2 and W24.

Occurrence and Description of Symptomatic Episodes During Cranberry Product Supplementation

Among the 202 women, 121 (59.9%) did not present any symptomatic episodes during cranberry extract supplementation, with similar proportions across groups (Table 3). The frequency of episodes was significantly reduced by 78.6%, 70.0%, and 67.9% in the 40G, 40SD, and FG groups, respectively, with no significant differences between groups.

Table 3.

Changes in Urinary Discomfort Episodes

	40SD					40G					FG
	Baseline1		6 Months of Intake		Significance (Baseline vs 6 Months)	Baseline1		6 Months of Intake		Significance (Baseline vs 6 Months)	Baseline1		6 months of Intake		Significance (Baseline vs 6 Months)
All women (n=202)
Women without episodes n (%)	0	(0)	39	(58)		0	(0)	45	(64)		0	(0)	37	(56)
Frequency, mean (SD)	3.0	(2.5)	0.9	(1.8)	P<0.001	2.8	(1.8)	0.6	(1.0)	P<0.001	2.8	(1.6)	0.9	(1.4)	P<0.001
Antibiotics, mean (SD)	1.1	(0.9)	0.4	(0.8)	P<0.001	1.4	(1.1)	0.3	(0.9)	P<0.001	1.5	(1.0)	0.2	(0.6)	P<0.001
Women with at least one episode during supplementation (n=81)
Frequency, mean (SD)	3.3	(1.9)	2.3	(2.2)	P=0.005	2.8	(1.5)	1.6	(1.0)	P=0.005	3.2	(2.0)	2.1	(1.5)	P=0.014
Duration, mean (SD)	5.8	(5.1)	1.6	(0.9)	P<0.001	4.3	(2.1)	1.8	(1.1)	P=0.001	3.8	(1.4)	1.4	(0.8)	P<0.001
Antibiotics, mean (SD)	1.1	(1.1)	0.7	(1.0)	NS	1.4	(1.2)	0.9	(1.4)	NS	1.6	(1.1)	0.4	(0.7)	P<0.001

Note: ¹ Frequencies from the 12 previous months were adjusted to 6 months. Bold values indicate significant differences vs baseline.(p value <0.05).

Abbreviations: NS, not statistically significant; SD, standard deviation.

Women who experienced at least one episode (n = 81, 40.1%) reported at least one cystitis episode (n = 60, 29.7%) and/or a cystitis-like episode (n = 39, 19.3%). These women also experienced a significantly reduced frequency of symptomatic episodes, −42.9% in the 40G group, −30.3% in the 40SD group, and −37.5% in the FG group, with no significant differences between groups. In women who experienced at least one episode during supplementation, the episode duration was significantly shorter: 2.4-fold shorter in the 40G group, 2.7-fold shorter in the FG group, and up to 3.6-fold shorter in the 40SD group. The reduced occurrence of symptomatic episodes led to a significant reduction in antibiotic use, with no significant differences between groups. During supplementation, the frequency and duration of cystitis and cystitis-like episodes were similar between the groups.

Acute Cystitis Symptom Scores for All Types of Episodes During Cranberry Extract Supplementation

The mean ACSS-Total scores and domain scores reported by women who experienced symptomatic episodes during cranberry product supplementation are presented in Table 4. Overall, the ACSS-Total scores markedly decreased compared with the baseline values (Table 2), indicating less severe urinary symptoms during episodes occurring with supplementation. Except for the score on the ACSS-Differential domain, which was significantly improved in the 40G group compared with the other groups, no significant differences were observed between groups in the ACSS-Total or other domain scores across all episodes, cystitis-like episodes, or cystitis episodes. The ACSS-Differential domain includes four items assessing symptoms related to adjacent or related organ involvement (Q7–Q10). Considering the individual ACSS items for which significant differences between groups were observed (Table 5), the improvements were predominantly in favour of the 40G group (11, 4, and 0 items improved compared with those of the other groups for 40G, 40SD, and FG, respectively). Improvements in the 40G group were observed for all episodes (Q4, Q7, Q10, and Q12), cystitis episodes (Q4, Q7, and Q10), and cystitis-like episodes (Q7, Q9, Q10, and Q12).

Table 4.

ACSS-Total and Domain Scores for Urinary Discomfort Episodes (All, Cystitis-Like and Cystitis Episodes) During Supplementation

	40SD (n=28)		40G (n=25)		FG (n=28)		Significance (Between Groups)
	Mean	SD	Mean	SD	Mean	SD
All episodes (n=81)
ACSS-Total	10.7	4.5	10.2	4.7	11.8	6.2	NS
ACSS-Typical	5.9	2.3	5.8	2.9	5.9	0.5	NS
ACSS-Differential	1.2	1.2	0.9	1.3	1.5	1.2	NS
ACSS-QoL	3.7	1.2	3.5	1.8	4.2	3.8	NS
Cystitis-like episodes (n=39)
ACSS-Total	7.6	6.4	5.7	4.9	6.5	4.0	NS
ACSS-Typical	4.0	3.1	3.2	2.7	2.3	1.6	NS
ACSS-Differential	0.9a	1.4	0.3a	0.5	1.7b	1.7	P<0.001
ACSS-QoL	3.1	2.7	2.2	2.3	2.6	1.9	NS
Cystitis episodes (n=60)
ACSS-Total	12.1	5.5	11.5	5.4	13.7	6.4	NS
ACSS-Typical	6.6	3.1	6.7	3.3	7.4	3.7	NS
ACSS-Differential	1.3	1.2	1.0	1.3	1.3	1.5	NS
ACSS-QoL	4.2	2.2	3.9	2.2	4.8	2.4	NS

Note: ^{a, b} Different letters and bold values indicate significant differences between groups (p value <0.05).

Abbreviations: NS, not statistically significant; SD, standard deviation.

Table 5.

Significant Differences in ACSS Responses Between Groups Among Women Who Experienced at Least One Urinary Discomfort Episode During the 6-month Supplementation Period

	40SD				40G				FG
	No (%)	Yes, Mild (%)	Yes, Mode Rate (%)	Yes, Severe (%)	No (%)	Yes, Mild (%)	Yes, Mode Rate (%)	Yes, Severe (%)	No (%)	Yes, Mild (%)	Yes, Mode Rate (%)	Yes, Severe (%)	Significance (Between Groups)
All episodes (n=81)
Q4: Incomplete bladder emptying	32.1 b	38.7 b	25.5 b	3.8 b	57.3 a	31.7 a	8.5 a	2.4 a	45.0	35.0	12.5	7.5	P<0.01
Q5: Pain or uncomfortable pressure in the lower abdomen	30.6 b	48.1 b	18.5 b	2.8 b	35.4 a	35.4 a	14.6 a	14.6 a	42.5 a	21.3 a	20 a	16.3 a	P<0.01
Q7: Loin (low back) pain (may be limited to only one side of the body)	65.7 b	23.1 b	9.3 b	1.9 b	92.7 a	4.9 a	2.4 a	0.0 a	60.0 b	26.3 b	12.5 b	1.3 b	P<0.001
Q8: Vaginal discharge (especially in the morning)	75.9 b	23.1 b	0.9 b	0.0 b	64.6 a	25.6 a	7.3 a	2.4 a	64.6 a	25.3 a	5.1 a	5.1 a	P<0.05
Q10: High body temperature	75.7 b	20.6 b	3.7 b	0.0 b	92.7 a	7.3 a	0.0 a	0.0 a	78.8 b	18.8 b	2.5 b	0.0 b	P<0.05
Q12. The extent to which normal work/everyday activities were affected by your symptoms in the past 24 hours1	15.7 b	51.9 b	24.1 b	8.3 b	34.1 a	40.2 a	19.5 a	6.1 a	13.8 b	47.5 b	28.8 b	10.0 b	P<0.05
Cystitis episodes (n=60)
Q4: Incomplete bladder emptying	24.0b	41.3b	29.3b	5.3 b	45.8a	43.8a	6.3a	4.2a	28.3	43.4	17.0	11.3	P<0.05
Q5: Pain or uncomfortable pressure in the lower abdomen	26.0 b	51.9 b	19.5 b	2.6 b	25.0a	37.5 a	16.7 a	20.8 a	35.8 a	15.1 a	24.5 a	24.5 a	P<0.001
Q7: Loin (low back) pain (may be limited to only one side of the)	58.4 b	28.6 b	10.4 b	2.6 b	91.7 a	4.2 a	4.2 a	0.0 a	62.3 b	26.4 b	9.4 b	1.9 b	P<0.01
Q8: Vaginal discharge (especially in the morning)	76.6 b	23.4 b	0.0 b	0.0 b	52.1 a	31.3 a	12.5 a	4.2 a	65.4 a	23.1 a	5.8 a	5.8 a	P<0.01
Q10: High body temperature	70.1 b	24.7 b	5.2 b	0.0 b	93.8 a	6.3 a	0.0 a	0.0 a	88.7 a	9.4 a	1.9 a	0.0 a	P<0.01
Cystitis-like episodes (n=39)
Q7: Loin (low back) pain (may be limited to only one side of the body)	83.9	9.7	6.5	0.0	94.1 a	5.9 a	0.0 a	0.0 a	55.6 b	25.9 b	18.5 b	0.0 b	P<0.01
Q9: Urethral discharge (without urination)	80.6 b	6.5 b	12.9 b	0.0 b	100.0 a	0.0 a	0.0 a	0.0 a	92.6	3.7	3.7	0.0	P<0.05
Q10: High body temperature	90.0 a	10.0 a	0.0 a	0.0 a	91.2 a	8.8 a	0.0 a	0.0 a	59.3 b	37.0 b	3.7 b	0.0 b	P<0.01
Q12. The extent to which normal work/everyday activities were affected by your symptoms in the past 24 hours1	38.7	35.5	19.4	6.5	55.9 a	32.4 a	5.9 a	5.9 a	22.2 b	66.7 b	11.1 b	0.0 b	P<0.05

Notes: ¹ Response modalities: Not at all, Mildly affected, Moderately affected, Extremely affected. ^{a, b} Different letters indicate significant differences between 2 groups (p value <0.05). Underlined and bold values indicate that the improvements were predominantly in favour of the 40G group (11 items improved compared with those of the other groups). Underlined values indicate a favourable trend for the cranberry product.

Overall, compared with the other groups, the 40G group showed greater improvement in symptoms related to adjacent organs and global symptom perception, including incomplete bladder emptying (Q4), kidney area pain (Q7), vaginal discharge (Q8), urethral discharge (Q9), body temperature (Q10), and effect of the symptom burden on work or daily activities (Q12).

Quality of Life (SF-Qualiveen) and Psychosocial Impact of Symptomatic Episodes After Cranberry Extract Supplementation

As shown in Figure 3, after 6 months of cranberry product supplementation, SF-Qualiveen total scores were significantly reduced in all groups (−0.6 ± 0.6 in the 40SD group, −0.7 ± 0.9 in the FG group, and −0.8 ± 0.7 in the 40G group). Domain scores were also significantly reduced, particularly in the “Bothered with limitations” (−58%) and “Constraints” (−43%) domains, both reaching the minimal important difference of 0.5, corresponding to a clinically meaningful change over time as defined by Bonniaud et al.42 Except for changes in the “Fears” domain (embarrassment due to bladder problems and concern about bladder symptoms), which differed significantly between the 40G and 40SD groups (−0.7 ± 0.9 [−54%] vs −0.3 ± 0.9 [−20%], p = 0.0205), changes in SF-Qualiveen total and domain scores were similar between groups. While SF-Qualiveen scores improved significantly at 3 or 6 months regardless of the group, a significant improvement in the total SF-Qualiveen score (−0.2 ± 0.6, p = 0.0039) was observed as early as the first month of supplementation only in the 40G group. Overall, the 40G group showed some significant improvements in SF-Qualiveen outcomes compared with the other groups.

Figure 3.

SF-Qualiveen total and domain scores at the baseline (dotted bars) and after 6 months of cranberry extract supplementation (solid bars) in the 40SD, 40G and FG groups. * Indicates a significant difference (p<0.05) between baseline and final scores. a: indicates significant differences (p<0.05) between two groups.

Compared with the baseline, the psychosocial impact of urinary tract discomfort was similarly improved across groups at week 24, as all scores were significantly increased in the FG group and most scores were significantly increased in the 40G and 40SD groups (Table 6). Changes in the sum of the item scores from baseline were +1.8, +3.4, and +2.0 at 1 month and +4.3, +5.0, and +6.6 at 6 months for the 40SD, 40G, and FG groups, respectively. Among the eight items on the questionnaire, the main baseline concerns were “mood,” “fear of not having access to toilets,” “fear of toilet cleanliness and urinary infection risk,” and “fear of insufficient water intake,” all of which significantly improved in the FG and 40G groups after supplementation.

Table 6.

Psychosocial Impact of Urinary Tract Discomfort at Baseline and After 6 months of Supplementation

	40SD (n=67)					40G (n=70)					FG (n=65)
	Baseline		6 Months		Significance	Baseline		6 Months		Significance	Baseline		6 Months		Significance
	Mean	SD	Mean	SD	(Baseline vs 6 Months)	Mean	SD	Mean	SD	(Baseline vs 6 Months)	Mean	SD	Mean	SD	(Baseline vs 6 Months)
Moods	−1.1	1.0	−0.4	1.2	P<0.0001	−1.2	0.9	−0.6	1.2	P=0.0001	−1.2	0.9	−0.4	1.2	P<0.0001
Ability to relax	0.6	0.8	1.1	0.8	P<0.0001	0.5	0.8	1.0	0.8	P<0.0001	0.4	0.8	1.0	0.9	P<0.0001
Sexual life	0.4	0.8	0.7	0.8	P=0.0005	0.2	0.9	0.8	0.9	P<0.0001	0.2	0.7	0.7	1.0	P<0.0001
Fear of UTI after sex	0.1	1.0	0.8	0.9	P<0.0001	0.2	1.2	0.7	1.0	P=0.0014	0.3	1.0	0.7	1.1	P=0.0039
Fear of not being able to urinate after sex	0.0	1.4	0.3	1.3	NS	−0.3	1.3	0.2	1.4	P=0.0131	−0.5	1.1	0.4	1.3	P<0.0001
Fear of urinating during sex	0.1	1.4	0.4	1.4	P=0.0267	0.0	1.4	0.3	1.5	NS	0.0	1.5	0.5	1.4	P=0.0071
Fear of wearing tight clothes	0.3	1.3	0.3	1.4	NS	0.0	1.4	0.4	1.4	P=0.0246	0.0	1.4	0.7	1.2	P=0.0005
Fear of not having access to the toilet	−0.9	1.1	−0.5	1.3	P=0.0023	−0.8	1.2	−0.2	1.4	P=0.0041	−0.9	1.2	−0.2	1.4	P=0.0004
Fear of the cleanliness of the toilets and UTI risk	−1.0	1.2	−0.8	1.2	NS	−1.1	1.2	−0.8	1.2	P=0.0251	−1.2	1.0	−0.6	1.3	P=0.0001
Fear of using a tampon during menstruation	0.0	1.4	0.4	1.3	P=0.0334	0.0	1.4	0.3	1.4	NS	−0.2	1.5	0.3	1.4	P=0.0135
Fear of not drinking enough water	−1.0	1.2	−0.5	1.4	P=0.0043	−0.9	1.2	−0.5	1.3	P=0.0122	−0.9	1.2	−0.5	1.3	P<0.0001

Abbreviations: NS, not statistically significant; SD, standard deviation.

Safety Data

During the study, 13 women among the 217 participants in the safety population (6 in the 40G group, 4 in the 40SD group, and 7 in the FG group) reported nonserious adverse events that were possibly related to the extracts. These events mainly consisted of gastrointestinal disorders, which were primarily reported in the 40G and FG groups, and mostly occurred after approximately 4 weeks of supplementation.

Discussion

The characterization of the extracts highlighted significant differences in specific classes of compounds previously described in the literature as being involved in UTI-related activity, such as organic acids, several forms of PACs (dimeric, trimeric, oligomeric, and polymeric), anthocyanins, other phenolic compounds, and dietary fibre. In accordance with the origin and extraction process of cranberry fruits, the soluble fraction (derived from juice) is rich in organic acids, oligomeric PACs, and monomeric phenolic compounds. Resin adsorption, a standard process applied to soluble fractions, facilitates high purification of phenolic compounds while removing organic acids. In contrast, the insoluble fraction (derived from fruit pomace) is rich in total PACs, containing a low proportion of oligomeric PACs and monomeric phenolic compounds, and is consequently composed mainly of insoluble PACs with a relatively high degree of polymerization. Taken together, these data reinforce the importance of carefully selecting analytical methods for cranberry characterization, particularly in the context of the nature of the components and product standardization for ameliorating UTIs.

Based on the results of this study, a first interpretation is that standardization at 162 mg/day of total PACs (quantified by butanolysis, adapted from Bate-Smith) is relevant for the prevention of recurrent symptomatic UTI episodes and the improvement of urinary comfort, as all three formulations showed similar efficacy in terms of the global endpoints (urinary comfort, episode frequency, episode duration, and main ACSS and SF-Qualiveen scores), despite the significant differences in the PACs content assessed using the (BL-)DMAC method (36.5 mg/day for 40SD, 24.4 mg/day for 40G, and 15.9 mg/day for FG). These findings suggest that PACs other than the oligomeric forms measured using the (BL-)DMAC method are involved in the activity supporting UTI-related benefits. The 162 mg/day (Bate-Smith) standardization was proposed because it correlates with the 36 mg/day (BL-)DMAC dosage previously described in the literature as effective for ameliorating UTI and corresponds to the posology of 40SD, which can be considered here as a reference product.43 However, this correlation is relevant only when the ingredient is entirely derived from the soluble fruit fraction and not when insoluble fractions are included.

The FDA (2020) and EMA (2022; traditional use of Vaccinium macrocarpon Aiton) have recognized the benefits of cranberry for the prevention of recurrent uncomplicated UTIs, whereas ANSES and EFSA did not. Nevertheless, all the agencies highlighted limited and inconsistent scientific evidence, notably due to the insufficient characterization of the cranberry products tested. In this context, and based on the present findings, a standardization at 162 mg/day of total PACs measured by butanolysis appears more representative and could simplify the determination of cranberry posology regardless of the origin of the material.

In this study, we included pre- and perimenopausal women with recurrent urinary symptomatic episodes, a subpopulation known to respond to cranberry supplementation.19,20 As mentioned in several guidelines, recurrence is defined as uncomplicated and/or complicated UTIs occurring at least three times in the previous year or twice in the previous six months.5–8 The efficacy of cranberry-based products is generally evaluated in terms of alleviating symptoms of acute infections or reducing UTI recurrence in susceptible populations. However, as recently noted, very few clinical studies have investigated the effect of prophylactic treatment on the psychosocial impact of UTIs or the impairments of daily activities and sexual life.44

In the present study, improvements in urinary comfort and associated quality of life (ACSS-QoL) were chosen as the primary efficacy endpoints. Among the main findings, comparable, rapid, and progressive effects of the three cranberry-based products were observed, as women reported significant improvements in urinary comfort and quality of life related to urinary symptoms following supplementation. Similarly, both the quality of life assessed using the SF-Qualiveen questionnaire and the psychosocial impact of urinary episodes were significantly improved, confirming the clinical benefits of the three cranberry products. High compliance with supplementation throughout the study may have contributed to these results. Another relevant finding is the reduced use of antibiotics, likely resulting from the decreased frequency of symptomatic episodes. Among women who experienced at least one episode during the 6-month supplementation period, antibiotic use was significantly reduced in the FG group but nonsignificantly decreased in the 40SD and 40G groups. This difference may be explained by the higher baseline frequency of culture-confirmed episodes and antibiotic use in the FG group than in the other groups. Finally, the present data confirm the well-established safety profile of cranberry-based products, supporting their suitability for prophylactic use.

The results suggest that the three cranberry-based products may contribute to reducing urinary symptomatic episodes in women with recurrent UTIs, who were characterized by an average of 5.8 symptomatic episodes per year at baseline. Regardless of the cranberry product consumed, 60% of the women experienced no episodes during the 6-month supplementation period. In a previous study, 57% of women supplemented with a purified cranberry extract providing 37.0 mg/day of PACs quantified by the (BL-)DMAC method were recurrence-free during a one-year follow-up.45 These results are comparable to those observed in the present study, even though only 40SD provided a similar PACs dose quantified using this method, whereas 40G and FG provided 24.4 mg/day and 15.9 mg/day, respectively. In that study, however, only a nonsignificant trend in favour of the 37 mg PACs extract compared with the 1 mg dose was reported. To date, no clinical evidence is available that suggests that the PACs dosage quantified by (BL-)DMAC has a dose-dependent effect on reducing the risk of symptomatic urinary episodes.19,20

Among women who experienced urinary symptomatic episodes, the recurrence frequency was significantly reduced by two- to threefold. When the extracts were considered separately, this reduction corresponded to an average of 1.6 episodes over 6 months for 40G, 2.3 for 40SD, and 2.1 for FG. Fewer than two episodes over 6 months, as observed with 40G supplementation, corresponds to a nonrecurrent status according to current definitions.5–8 Although the non-placebo-controlled design of this study does not allow a direct assessment of a reduction in the recurrence risk, the results support a preventive effect of the tested cranberry products on urinary symptomatic episodes, which is consistent with recent meta-analyses and systematic reviews.19,20

Among the three extracts, 40G produced greater improvements than the other extracts in the ACSS-Differential domain for cystitis-like episodes (symptoms related to adjacent organs), in several ACSS items related to all episodes (incomplete bladder emptying, burden on daily activities), in the “Fears” domain of the SF-Qualiveen questionnaire, and in the earlier onset of significant effects in these questionnaires. Considering the differences in composition between this extract and the other extracts, the ratio of oligomeric to polymeric PACs appears to be of particular interest. Besides differences in PACs composition, increasing evidence suggests that interactions between cranberry compounds and the gut microbiota may also contribute to the clinical differences observed between formulations. In 2016, the EMA published a scientific opinion on the mode of action of PACs intended for UTI prevention: The bioavailability of PACs and A-PACs is not fully known. Oligomeric and polymeric PACs are usually not absorbed or to a low extent only (< 10%). There are no reports confirming the presence of PACs in the urine. Due to the very limited bioavailability of PACs it can be assumed that the concentrations needed for a mechanical mode of action are likely not be reached in the bladder. Therefore, a principal mode of action is highly unlikely.46 These conclusions suggest that directly bioavailable PACs alone (mainly soluble monomeric phenolic compounds and small oligomers) are unlikely to achieve effective urinary activity because of their low urinary concentrations. Increasing evidence therefore suggests that the preventive effects of cranberry are mediated mainly by bioavailable metabolites generated through gut microbiota metabolism rather than by intact PACs absorbed in the small intestine. A pilot human study demonstrated that directly bioavailable PACs detected in urine were not present at concentrations sufficient to exert antiadhesive activity, whereas gut microbiota-derived metabolites such as valerolactones and their derivatives were identified in urine and exhibited ex vivo antiadhesive activity against E. coli.47 Other studies confirmed the activity of valerolactones and notably extended potent microbiota metabolites from cranberry to coumaric acids, hippuric acids and phenylacetic acids and confirmed their ability to prevent E. coli and C. albicans adhesion and improve the barrier function of the uroepithelium.48–50

Another mechanism may involve the gut–bladder axis.51–53 The gut is considered a reservoir for bladder colonization, and women with recurrent UTIs have been shown to exhibit gut dysbiosis, particularly reduced short-chain fatty acid (SCFA) production. Changes in E. coli and Lactobacillus populations are of particular interest, as cranberry-derived compounds reaching the colon may inhibit E. coli growth while promoting Lactobacillus growth,54 thereby restoring a protective bladder ecosystem dominated by Lactobacillus species, which have demonstrated inhibitory activity against E. coli.55,56 These gut-mediated mechanisms may explain why the formulation containing a higher proportion of polymeric PACs (40G) produced greater clinical benefits than the soluble extract (40SD).

The main limitations of this study are related to its design. As a comparative observational study, it lacked a placebo control group, preventing a direct assessment of the reduction in the relative risk of UTIs associated with the cranberry products. Changes from the baseline relied on retrospective data collected at enrolment and prospective data collected during the 6-month follow-up. Recall bias may have influenced subjective assessments, and the average episode severity could not be directly compared. In addition, the diagnosis of cystitis differed before supplementation (culture-confirmed UTI based on positive CBEU) and during supplementation (symptom-based assessment using ACSS-Q3 and ACSS-Q1 or Q2 scores). Nevertheless, the number of urinary episodes reported during the 12 months preceding enrolment can be considered sufficiently reliable for comparison with episodes reported during the follow-up period.

Conclusions

The principal contribution of this study is the direct clinical comparison of three cranberry formulations with markedly different PACs profiles and other putative actives (such as organic acids) supported by extensive compositional characterization. The results support the potential benefit of cranberry formulation standardized to 162mg of total PACs (rather than standardisation in 36mg soluble PACs) for improving urinary comfort, reducing symptomatic episodes and improving quality of life in women with recurrent UTIs.

The specific compositional profile of one extract (40G), notably its balance of polymeric PACs, showed additional benefits related to symptom severity involving adjacent organs and quality of life. Given the observational design and absence of a placebo group, confirmation in randomized controlled studies remains warranted. Further studies are also warranted to better elucidate the mechanisms of action of these three formulations and with this specific PACs profile, particularly those mediated by the gut microbiota.

Funding Statement

This study was funded by Nexira, France.

Abbreviations

ACSS, Acute Cystitis Symptom Score; ANSES, French Agency for Food, Environmental and Occupational Health and Safety; BL-DMAC, Butanolysis (Bate-Smith)/DMAC method; CBEU, Cytobacteriological examination of urine; EFSA, European Food Safety Authority; EMA, European Medicines Agency; FDA, Food and Drug Administration; FG, 40G, 40SD, Cranberry extract codes; FG, Fruit/ground extract (includes an insoluble fraction); 40G, specific extract with a unique oligomeric/polymeric PACs ratio; 40SD, soluble fraction (standard juice extract); UTI, Urinary Tract Infection; PACs, Proanthocyanidins; VAS, Visual analogue scale; QoL, Quality of life; SD, Standard deviation; SF-Qualiveen, Short form of the Qualiveen Questionnaire; W2, W24, Week 2, Week 24.

Data Sharing Statement

The datasets generated and/or analysed during the current study are available from the corresponding author upon reasonable request. Due to the observational nature of this study and the inclusion of personal health information, data from individual participants cannot be made publicly available to ensure privacy and compliance with French regulations in force at the time of this study. Requests for access to the minimal dataset necessary to interpret and replicate the findings can be addressed to the corresponding author.

Ethical Approval and Consent to Participate

In accordance with French regulations, this study was approved by the Independent Review Board of Sud-Est VI (2019 / CE 51).The study was conducted in accordance with the ethical principles of the Declaration of Helsinki and its subsequent amendments. All participants received written information about the study and confirmed that they did not object to participation, in accordance with the French legislation in force at the time of this study for observational studies.

Author Contributions

All authors made a significant contribution to the work reported, whether that is in the conception, study design, execution, acquisition of data, analysis and interpretation, or in all these areas; took part in drafting, revising or critically reviewing the article; gave final approval of the version to be published; have agreed on the journal to which the article has been submitted; and agree to be accountable for all aspects of the work.

Disclosure

DG is a full-time employee of Nexira. EM is a full-time employee of INRAE.

CJ, FH and FR are full-time employees of CEN. The authors declare that they have no other financial or nonfinancial competing interests and that no personal payments were received in relation to this study.