Alpha-linolenic acid associations with disability and brain volume in multiple sclerosis: a brief replication report.
The 5 matches
- [1] § Method ↔ analyse.R, lines 618–699 · score 0.62 · annual rate, T1w lesions, disease duration, mediating, longitudinal, mediation
- [2] § Results ↔ analyse.R, lines 618–699 · score 0.58 · annual relapses, annual rate, T1w lesions, brain volume, Baseline, PASAT
- [3] § Method ↔ data_prep.R, lines 1–45 · score 0.57 · Serum alpha linolenic, acid, scores, MRI, MS, PASAT
- [4] § Method ↔ analyse.R, lines 505–543 · score 0.56 · negative binomial model, linear models, intracranial volume, relapses, treatment, sex
- [5] § Method ↔ analyse.R, lines 1–33 · score 0.52 · Serum alpha linolenic, acid, MS, PASAT, EDSS
Paper
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The authors' code
R · 699 lines · 26 KB · no license · 4 matches
- # Replication of Serum Alpha-Linolenic Acid and Long-Term Multiple Sclerosis Activity and Progression
- #
- # Max Korbmacher, Jul 2025
- #
- # ------------------------------------------------------------ #
- # ---------------------- Contents ---------------------------- #
- # ------------------------------------------------------------ #
- # 0. Preparations -------------------------------------------- #
- # 1. Descriptives & Validation ------------------------------- #
- # 2. Analyse ------------------------------------------------- #
- # 2.1 Mixed linear models ------------------------------------ #
- # 2.2 Mixed negative binomial models ------------------------- #
- # 3. Simple linear models ------------------------------------ #
- # 3.1 T2w number of lesions --------------------------------- #
- # 3.2 Brain volume ------------------------------------------ #
- # 3.3 PASAT ------------------------------------------------- #
- # 3.4 EDSS -------------------------------------------------- #
- # 3.5 T1w new Lesions (Negative binomial models) ------------- #
- # 4. Mediation analyses -------------------------------------- #
- # 4.1 Brain vol > ALA > EDSS---------------------------------- #
- # 4.2 T1w lesions > ALA > EDSS-------------------------------- #
- # 5. Longitudinal predictions of ALA ------------------------- #
- # 6. Disease Duration instead of Age as Covariate------------- #
- # ------------------------------------------------------------ #
- # ------------------------------------------------------------ #
- #
- # 0. Preparations --------------------------------------------
- # clean up
- rm(list = ls(all.names = TRUE)) # clear all objects includes hidden objects.
- gc() #free up memory and report the memory usage.
- # define data path
- datapath = "/Users/max/Documents/Local/MS/ALA/data/"
- # read packages
- pacman::p_load(haven,dplyr,reshape2,lme4,lmerTest,VGAM,mediation, psych, MuMIn, reshape2, tidyr)
- # load data
- df = read.csv(paste(datapath,"clean.csv",sep=""))
- long = read.csv(paste(datapath,"rate_of_change_10yrs.csv",sep=""))
- relapse = read.csv(paste(datapath,"relapses_long.csv",sep=""))
- #
- # 1. Descriptives & Validation -------------------------------
- ICC(reshape(df%>%dplyr::select(eid,session,ALA),
- idvar = "eid", timevar = "session",
- direction = "wide") %>% dplyr::select(-eid))
- # Descriptive table
- relapse %>%
- group_by(session) %>%
- summarise(
- across(
- c(RELAPSENEW, DiseaseDuration),
- list(
- mean = ~mean(., na.rm = TRUE),
- sd = ~sd(., na.rm = TRUE),
- N = ~sum(!is.na(.))
- )
- )
- ) %>%
- pivot_longer(
- cols = -session,
- names_to = c("variable", "stat"),
- names_sep = "_"
- ) %>%
- pivot_wider(
- names_from = session,
- values_from = value
- )
- Table1 = df %>%
- group_by(session) %>%
- summarise(
- across(
- c(age, ALA, new_T1Gd_lesion, TotalVol, lesion_count, edss, PASAT),
- list(
- mean = ~mean(., na.rm = TRUE),
- sd = ~sd(., na.rm = TRUE),
- N = ~sum(!is.na(.))
- )
- ),
- .groups = "drop"
- ) %>%
- pivot_longer(
- cols = -session,
- names_to = c("variable", "stat"),
- names_pattern = "^(.*)_(mean|sd|N)$"
- ) %>%
- pivot_wider(
- names_from = session,
- values_from = value
- )
- print(Table1, n=100)
- range((df %>% filter(session==0))$ALA,na.rm = T)
- summarise_categorical <- function(data, vars) {
- data %>%
- pivot_longer(
- cols = {{ vars }},
- names_to = "variable",
- values_to = "category"
- ) %>%
- group_by(session, variable, category) %>%
- summarise(N = n(), .groups = "drop_last") %>%
- mutate(Percent = N / sum(N) * 100) %>%
- ungroup() %>%
- pivot_wider(
- names_from = session,
- values_from = c(N, Percent),
- names_glue = "{.value}_session{session}"
- )
- }
- # Categorical summary
- summarise_categorical(
- df,
- c(sex)
- )
- # last time point summary
- continuous_vars <- c(
- "Age_OFAMS10", "T1wLesions", "relapse_rate", "relapses_12mnths_before_baseline",
- "relapse_rate_prior", "Nb_of_relapses_FU", "EDSS_10_short", "TotalVol",
- "PASAT", "t2wLesions", "EDSS", "lesion_count_diff"
- )
- long %>%
- summarise(
- across(
- all_of(continuous_vars),
- list(
- mean = ~mean(., na.rm = TRUE),
- sd = ~sd(., na.rm = TRUE),
- N = ~sum(!is.na(.))
- )
- )
- ) %>%
- pivot_longer(
- everything(),
- names_to = c("variable", "stat"),
- names_pattern = "^(.*)_(mean|sd|N)$"
- ) %>%
- pivot_wider(
- names_from = stat,
- values_from = value
- )
- sum(na.omit(long$Nb_of_relapses_FU))
- sum(na.omit(long$T1wLesions))
- dd = ((merge(long, df%>%filter(session==0),by="eid"))$Age_OFAMS10-
- (merge(long, df%>%filter(session==0),by="eid"))$age.x+
- (merge(long, df%>%filter(session==0),by="eid"))$DiseaseDuration)
- paste("Disease duration at follow up is Mean = ",round(mean(na.omit(dd)),1),"±",round(sd(na.omit(dd)),1),sep="")
- # 2. Analyse -------------------------------------------------
- # 2.1 Mixed linear models ------------------------------------
- # 2.1.1 PASAT
- m = lmer(PASAT ~ log(ALA) + (1|eid),df)
- summary(m)
- m = lmer(PASAT ~ log(ALA) + age + sex + Treatment_OFAMS + (1|eid),df)
- summary(m)
- # 2.1.2 brain volume ***
- m = lmer(TotalVol ~ log(ALA) + EstimatedTotalIntraCranialVol + (1|eid),df)
- summary(m)
- effectsize::standardize_parameters(m)
- r.squaredGLMM(m)
- m = lmer(TotalVol ~ log(ALA) + age + sex + Treatment_OFAMS + EstimatedTotalIntraCranialVol + (1|eid),df)
- summary(m)
- effectsize::standardize_parameters(m)
- r.squaredGLMM(m)
- # # 2.1.2.1 GM volume *
- # m = lmer(TotalGrayVol ~ log(ALA) + EstimatedTotalIntraCranialVol + (1|eid),df)
- # summary(m)
- # effectsize::standardize_parameters(m)
- # m = lmer(TotalGrayVol ~ log(ALA) + age + sex + Treatment_OFAMS + EstimatedTotalIntraCranialVol + (1|eid),df)
- # summary(m)
- # effectsize::standardize_parameters(m)
- #
- # # 2.1.2.2 WM volume
- # m = lmer(TotalWMVol ~ log(ALA) + EstimatedTotalIntraCranialVol + (1|eid),df)
- # summary(m)
- # effectsize::standardize_parameters(m)
- # m = lmer(TotalWMVol ~ log(ALA) + age + sex + Treatment_OFAMS + EstimatedTotalIntraCranialVol + (1|eid),df)
- # summary(m)
- # effectsize::standardize_parameters(m)
- # 2.1.3 EDSS
- m = lmer(edss ~ log(ALA) + (1|eid),df)
- summary(m)
- effectsize::standardize_parameters(m)
- r.squaredGLMM(m)
- m = lmer(edss ~ log(ALA) + age + sex + Treatment_OFAMS + (1|eid),df)
- summary(m)
- effectsize::standardize_parameters(m)
- r.squaredGLMM(m)
- # 2.1.3 T2w number of lesions
- m = lmer(lesion_count ~ log(ALA) + (1|eid),df)
- summary(m)
- effectsize::standardize_parameters(m)
- # m = lmer(lesion_count ~ log(ALA) + age + sex + Treatment_OFAMS + (1|eid),df)
- # summary(m)
- # control also for intracranial volume
- m = lmer(lesion_count ~ log(ALA) + age + sex + Treatment_OFAMS + EstimatedTotalIntraCranialVol + (1|eid),df)
- summary(m)
- effectsize::standardize_parameters(m)
- # 2.2 Mixed negative binomial models --------------------------
- # 2.2.1 T1w new Lesions (Negative binomial models) ---------------------
- m = glmer(new_T1Gd_lesion ~ log(ALA) + (1|eid),df,family = binomial(link = cloglog))
- summary(m)
- m = glmer(new_T1Gd_lesion ~ log(ALA) +age + sex + Treatment_OFAMS + (1|eid),df,family = binomial(link = cloglog))
- summary(m)
- # control also for intracranial volume
- m = glmer(new_T1Gd_lesion ~ log(ALA) +age + sex + Treatment_OFAMS + EstimatedTotalIntraCranialVol + (1|eid),df,family = binomial(link = cloglog))
- summary(m)
- # 2.2.2 New relapse (Negative binomial models) ---------------------
- relapse = merge(relapse%>%dplyr::select(eid,session,RELAPSENEW),
- df%>%dplyr::select(eid,session,ALA,sex,age,Treatment_OFAMS),
- by=c("eid","session"))
- relapse$RELAPSENEW = ifelse(is.na(relapse$RELAPSENEW) == T, 0,relapse$RELAPSENEW)
- m = glmer(RELAPSENEW ~ log(ALA) + (1|eid),relapse,family = binomial(link = cloglog))
- summary(m)
- m = glmer(RELAPSENEW ~ log(ALA) +age + sex +Treatment_OFAMS+ (1|eid),relapse,family = binomial(link = cloglog))
- summary(m)
- # 3. Simple linear models ------------------------------------
- # 3.1 T2w number of lesions -----------------------------------------
- # including ICV
- m = lm(lesion_count ~ log(ALA) + age + sex + EstimatedTotalIntraCranialVol,df%>%filter(session==0))
- summary(m)
- effectsize::standardize_parameters(m)
- m = lm(lesion_count ~ log(ALA) + age + sex + Treatment_OFAMS + EstimatedTotalIntraCranialVol,df%>%filter(session==12))
- summary(m)
- m = lm(lesion_count ~ log(ALA) + age + sex + Treatment_OFAMS + EstimatedTotalIntraCranialVol,df%>%filter(session==24))
- summary(m)
- # not including ICV
- m = lm(lesion_count ~ log(ALA) + age + sex ,df%>%filter(session==0))
- summary(m)
- m = lm(lesion_count ~ log(ALA) + age + sex + Treatment_OFAMS,df%>%filter(session==12))
- summary(m)
- m = lm(lesion_count ~ log(ALA) + age + sex + Treatment_OFAMS,df%>%filter(session==24))
- summary(m)
- # 3.2 Brain volume -----------------------------------------
- # including ICV
- m = lm(TotalVol ~ log(ALA) + age + sex + EstimatedTotalIntraCranialVol,df%>%filter(session==0))
- summary(m)
- m = lm(TotalVol ~ log(ALA) + age + sex + Treatment_OFAMS + EstimatedTotalIntraCranialVol,df%>%filter(session==12))
- summary(m)
- m = lm(TotalVol ~ log(ALA) + age + sex + Treatment_OFAMS + EstimatedTotalIntraCranialVol,df%>%filter(session==24))
- summary(m)
- # not including ICV
- m = lm(TotalVol ~ log(ALA) + age + sex ,df%>%filter(session==0))
- summary(m)
- m = lm(TotalVol ~ log(ALA) + age + sex + Treatment_OFAMS,df%>%filter(session==12))
- summary(m)
- m = lm(TotalVol ~ log(ALA) + age + sex + Treatment_OFAMS,df%>%filter(session==24))
- summary(m)
- # 3.3 PASAT -----------------------------------------
- m = lm(PASAT ~ log(ALA),df%>%filter(session==0))
- summary(m)
- m = lm(PASAT ~ log(ALA) + age + sex,df%>%filter(session==0))
- summary(m)
- m = lm(PASAT ~ log(ALA),df%>%filter(session==12))
- summary(m)
- m = lm(PASAT ~ log(ALA) + age + sex + Treatment_OFAMS,df%>%filter(session==12))
- summary(m)
- m = lm(PASAT ~ log(ALA),df%>%filter(session==24))
- summary(m)
- m = lm(PASAT ~ log(ALA) + age + sex + Treatment_OFAMS,df%>%filter(session==24))
- summary(m)
- # 3.4 EDSS -----------------------------------------
- m = lm(edss ~ log(ALA),df%>%filter(session==0))
- summary(m)
- m = lm(edss ~ log(ALA) + age + sex,df%>%filter(session==0))
- summary(m)
- m = lm(edss ~ log(ALA),df%>%filter(session==12))
- summary(m)
- effectsize::standardize_parameters(m)
- m = lm(edss ~ log(ALA) + age + sex + Treatment_OFAMS,df%>%filter(session==12))
- summary(m)
- m = lm(edss ~ log(ALA),df%>%filter(session==24))
- summary(m)
- effectsize::standardize_parameters(m)
- m = lm(edss ~ log(ALA) + age + sex + Treatment_OFAMS,df%>%filter(session==24))
- summary(m)
- effectsize::standardize_parameters(m)
- # 3.5 T1w new Lesions (Negative binomial models) ---------------------
- # BL
- m = glm(new_T1Gd_lesion ~ log(ALA),df%>%filter(session==0),family = binomial(link = cloglog))
- summary(m)
- m = glm(new_T1Gd_lesion ~ log(ALA) +age + sex + Treatment_OFAMS ,df%>%filter(session==0),family = binomial(link = cloglog))
- summary(m)
- # control also for intracranial volume
- m = glm(new_T1Gd_lesion ~ log(ALA) +age + sex + Treatment_OFAMS + EstimatedTotalIntraCranialVol,df%>%filter(session==0),family = binomial(link = cloglog))
- summary(m)
- # 12 months
- m = glm(new_T1Gd_lesion ~ log(ALA),df%>%filter(session==12),family = binomial(link = cloglog))
- summary(m)
- m = glm(new_T1Gd_lesion ~ log(ALA) +age + sex + Treatment_OFAMS ,df%>%filter(session==12),family = binomial(link = cloglog))
- summary(m)
- # control also for intracranial volume
- m = glm(new_T1Gd_lesion ~ log(ALA) +age + sex + Treatment_OFAMS + EstimatedTotalIntraCranialVol,df%>%filter(session==12),family = binomial(link = cloglog))
- summary(m)
- # 24 months
- m = glm(new_T1Gd_lesion ~ log(ALA),df%>%filter(session==24),family = binomial(link = cloglog))
- summary(m)
- m = glm(new_T1Gd_lesion ~ log(ALA) +age + sex + Treatment_OFAMS ,df%>%filter(session==24),family = binomial(link = cloglog))
- summary(m)
- # control also for intracranial volume
- m = glm(new_T1Gd_lesion ~ log(ALA) +age + sex + Treatment_OFAMS + EstimatedTotalIntraCranialVol,df%>%filter(session==24),family = binomial(link = cloglog))
- summary(m)
- # 4. Mediation analyses --------------------------------------
- detach(package:lmerTest,unload = T) # lmerTest needs to leave for these functions to work
- # 4.1 Brain vol > ALA > EDSS----------------------------------
- # select and log transform
- df2 = df %>% dplyr::select(eid,age,sex,Treatment_OFAMS,ALA,edss,TotalVol,lesion_count) #%>% na.omit
- df2$ALA = log(df2$ALA)
- # models
- fit.mediator = lmer(ALA ~ age + sex + Treatment_OFAMS + TotalVol + (1|eid),df2)
- fit.dv = lmer(edss ~ age + sex + Treatment_OFAMS + ALA + TotalVol + (1|eid),df2)
- # mediation
- results1 <- mediation::mediate(fit.mediator, fit.dv, mediator='ALA', treat = 'TotalVol')
- summary(results1)
- # 4.2 T1w lesions > ALA > EDSS--------------------------------
- # models
- fit.mediator = lmer(ALA ~ age + sex + Treatment_OFAMS + lesion_count + (1|eid),df2)
- fit.dv = lmer(edss ~ age + sex + Treatment_OFAMS + ALA + lesion_count + (1|eid),df2)
- # mediation
- results <- mediation::mediate(fit.mediator, fit.dv, mediator='ALA', treat = 'lesion_count')
- summary(results)
- # 5. Longitudinal predictions of ALA -------------------------
- # prep df
- long.df = merge(df %>% dplyr::filter(session == 0)%>%dplyr::select(eid,ALA,EstimatedTotalIntraCranialVol,Treatment_OFAMS),long, id.vars = "eid")
- # check associations of ALA with THE ANNUAL RATE OF CHANGE in ...
- ## EDSS
- m=lm(EDSS_diff~log(ALA),data=long.df)
- summary(m)
- m=lm(EDSS_diff ~log(ALA)+age + sex + Treatment_OFAMS,data=long.df)
- summary(m)
- effectsize::standardize_parameters(m)
- ## PASAT
- m=lm(PASAT_diff~log(ALA),data=long.df)
- summary(m)
- m=lm(PASAT_diff ~log(ALA)+age + sex + Treatment_OFAMS,data=long.df)
- summary(m)
- ## T2w lesions
- m=lm(lesion_count_diff~log(ALA),data=long.df)
- summary(m)
- m=lm(lesion_count_diff ~log(ALA)+age + sex + Treatment_OFAMS+EstimatedTotalIntraCranialVol,data=long.df)
- summary(m)
- ## Brain volume
- m=lm(TotalVol_diff~log(ALA),data=long.df)
- summary(m)
- m=lm(TotalVol_diff ~log(ALA)+age + sex + Treatment_OFAMS+EstimatedTotalIntraCranialVol,data=long.df)
- summary(m)
- ## [[total]] T1w lesions
- m=lm(T1wLesions~log(ALA),data=long.df)
- summary(m)
- m=lm(T1wLesions ~log(ALA)+age + sex + Treatment_OFAMS+EstimatedTotalIntraCranialVol,data=long.df)
- summary(m)
- ## relapse rate / annual relapses during 12 study years
- m=lm(relapse_rate~log(ALA),data=long.df)
- summary(m)
- effectsize::standardize_parameters(m)
- m=lm(relapse_rate ~log(ALA)+age + sex + Treatment_OFAMS,data=long.df)
- summary(m)
- effectsize::standardize_parameters(m)
- ## non-log transformed
- m=lm(relapse_rate~(ALA),data=long.df)
- summary(m)
- m=lm(relapse_rate ~(ALA)+age + sex + Treatment_OFAMS,data=long.df)
- summary(m)
- ## relapse rate / annual relapses during 12 study years + the year before
- m=lm(relapse_rate_prior~log(ALA),data=long.df)
- summary(m)
- m=lm(relapse_rate_prior ~log(ALA)+age + sex + Treatment_OFAMS,data=long.df)
- summary(m)
- effectsize::standardize_parameters(m)
- ## relapses prior baseline
- m=lm(relapses_12mnths_before_baseline~log(ALA),data=long.df)
- summary(m)
- m=lm(relapses_12mnths_before_baseline ~log(ALA)+age + sex + Treatment_OFAMS,data=long.df)
- summary(m)
- # 6. Disease Duration instead of Age as Covariate-------------
- # 2. Analyse -------------------------------------------------
- # 2.1 Mixed linear models ------------------------------------
- # 2.1.1 PASAT
- library(lmerTest)
- m = lmer(PASAT ~ log(ALA) + (1|eid),df)
- summary(m)
- m = lmer(PASAT ~ log(ALA) + age + sex + Treatment_OFAMS + (1|eid),df)
- summary(m)
- m = lmer(PASAT ~ log(ALA) + DiseaseDuration + sex + Treatment_OFAMS + (1|eid),df)
- summary(m)
- m = lmer(PASAT ~ log(ALA) +age + DiseaseDuration + sex + Treatment_OFAMS + (1|eid),df)
- summary(m)
- # 2.1.2 brain volume ***
- m = lmer(TotalVol ~ log(ALA) + EstimatedTotalIntraCranialVol + (1|eid),df)
- summary(m)
- effectsize::standardize_parameters(m)
- r.squaredGLMM(m)
- m = lmer(TotalVol ~ log(ALA) + age + sex + Treatment_OFAMS + EstimatedTotalIntraCranialVol + (1|eid),df)
- summary(m)
- effectsize::standardize_parameters(m)
- r.squaredGLMM(m)
- m = lmer(TotalVol ~ log(ALA) + DiseaseDuration + sex + Treatment_OFAMS + EstimatedTotalIntraCranialVol + (1|eid),df)
- summary(m)
- effectsize::standardize_parameters(m)
- r.squaredGLMM(m)
- # # 2.1.2.1 GM volume *
- # m = lmer(TotalGrayVol ~ log(ALA) + EstimatedTotalIntraCranialVol + (1|eid),df)
- # summary(m)
- # effectsize::standardize_parameters(m)
- # m = lmer(TotalGrayVol ~ log(ALA) + age + sex + Treatment_OFAMS + EstimatedTotalIntraCranialVol + (1|eid),df)
- # summary(m)
- # effectsize::standardize_parameters(m)
- #
- # # 2.1.2.2 WM volume
- # m = lmer(TotalWMVol ~ log(ALA) + EstimatedTotalIntraCranialVol + (1|eid),df)
- # summary(m)
- # effectsize::standardize_parameters(m)
- # m = lmer(TotalWMVol ~ log(ALA) + age + sex + Treatment_OFAMS + EstimatedTotalIntraCranialVol + (1|eid),df)
- # summary(m)
- # effectsize::standardize_parameters(m)
- # 2.1.3 EDSS
- m = lmer(edss ~ log(ALA) + (1|eid),df)
- summary(m)
- effectsize::standardize_parameters(m)
- r.squaredGLMM(m)
- m = lmer(edss ~ log(ALA) + age + sex + Treatment_OFAMS + (1|eid),df)
- summary(m)
- m = lmer(edss ~ log(ALA) + DiseaseDuration + sex + Treatment_OFAMS + (1|eid),df)
- summary(m)
- effectsize::standardize_parameters(m)
- r.squaredGLMM(m)
- # 2.1.3 T2w number of lesions
- m = lmer(lesion_count ~ log(ALA) + (1|eid),df)
- summary(m)
- effectsize::standardize_parameters(m)
- m = lmer(lesion_count ~ log(ALA) + DiseaseDuration+ (1|eid),df)
- summary(m)
- effectsize::standardize_parameters(m)
- # m = lmer(lesion_count ~ log(ALA) + age + sex + Treatment_OFAMS + (1|eid),df)
- # summary(m)
- # control also for intracranial volume
- m = lmer(lesion_count ~ log(ALA) + age + sex + Treatment_OFAMS + EstimatedTotalIntraCranialVol + (1|eid),df)
- summary(m)
- effectsize::standardize_parameters(m)
- m = lmer(lesion_count ~ log(ALA) + DiseaseDuration + sex + Treatment_OFAMS + EstimatedTotalIntraCranialVol + (1|eid),df)
- summary(m)
- # 2.2 Mixed negative binomial models --------------------------
- # 2.2.1 T1w new Lesions (Negative binomial models) ---------------------
- m = glmer(new_T1Gd_lesion ~ log(ALA) + (1|eid),df,family = binomial(link = cloglog))
- summary(m)
- m = glmer(new_T1Gd_lesion ~ log(ALA) +age + sex + Treatment_OFAMS + (1|eid),df,family = binomial(link = cloglog))
- summary(m)
- m = glmer(new_T1Gd_lesion ~ log(ALA) +DiseaseDuration + sex + Treatment_OFAMS + (1|eid),df,family = binomial(link = cloglog))
- summary(m)
- # control also for intracranial volume
- m = glmer(new_T1Gd_lesion ~ log(ALA) +age + sex + Treatment_OFAMS + EstimatedTotalIntraCranialVol + (1|eid),df,family = binomial(link = cloglog))
- summary(m)
- m = glmer(new_T1Gd_lesion ~ log(ALA) +DiseaseDuration + sex + Treatment_OFAMS + EstimatedTotalIntraCranialVol + (1|eid),df,family = binomial(link = cloglog))
- summary(m)
- # 2.2.2 New relapse (Negative binomial models) ---------------------
- relapse = merge(relapse%>%dplyr::select(eid,session,RELAPSENEW),
- df%>%dplyr::select(eid,session,ALA,sex,age,Treatment_OFAMS),
- by=c("eid","session"))
- relapse$RELAPSENEW = ifelse(is.na(relapse$RELAPSENEW) == T, 0,relapse$RELAPSENEW)
- m = glmer(RELAPSENEW ~ log(ALA) + (1|eid),relapse,family = binomial(link = cloglog))
- summary(m)
- m = glmer(RELAPSENEW ~ log(ALA) +age + sex +Treatment_OFAMS+ (1|eid),relapse,family = binomial(link = cloglog))
- summary(m)
- # 3. Simple linear models ------------------------------------
- # 3.1 T2w number of lesions -----------------------------------------
- # including ICV
- m = lm(lesion_count ~ log(ALA) + DiseaseDuration + sex + EstimatedTotalIntraCranialVol,df%>%filter(session==0))
- summary(m)
- effectsize::standardize_parameters(m)
- m = lm(lesion_count ~ log(ALA) + age + DiseaseDuration + sex + Treatment_OFAMS + EstimatedTotalIntraCranialVol,df%>%filter(session==0))
- summary(m)
- m = lm(lesion_count ~ log(ALA) + age + sex + Treatment_OFAMS + EstimatedTotalIntraCranialVol,df%>%filter(session==0))
- summary(m)
- m = lm(lesion_count ~ log(ALA) + DiseaseDuration + sex + Treatment_OFAMS + EstimatedTotalIntraCranialVol,df%>%filter(session==12))
- summary(m)
- m = lm(lesion_count ~ log(ALA) + DiseaseDuration + sex + Treatment_OFAMS + EstimatedTotalIntraCranialVol,df%>%filter(session==24))
- summary(m)
- # not including ICV
- m = lm(lesion_count ~ log(ALA) + DiseaseDuration + sex ,df%>%filter(session==0))
- summary(m)
- m = lm(lesion_count ~ log(ALA) + DiseaseDuration + sex + Treatment_OFAMS,df%>%filter(session==12))
- summary(m)
- m = lm(lesion_count ~ log(ALA) + age + sex + Treatment_OFAMS,df%>%filter(session==24))
- summary(m)
- # 3.2 Brain volume -----------------------------------------
- # including ICV
- m = lm(TotalVol ~ log(ALA) + age + sex + EstimatedTotalIntraCranialVol,df%>%filter(session==0))
- summary(m)
- m = lm(TotalVol ~ log(ALA) + age + sex + Treatment_OFAMS + EstimatedTotalIntraCranialVol,df%>%filter(session==12))
- summary(m)
- m = lm(TotalVol ~ log(ALA) + age + sex + Treatment_OFAMS + EstimatedTotalIntraCranialVol,df%>%filter(session==24))
- summary(m)
- # not including ICV
- m = lm(TotalVol ~ log(ALA) + age + sex ,df%>%filter(session==0))
- summary(m)
- m = lm(TotalVol ~ log(ALA) + age + sex + Treatment_OFAMS,df%>%filter(session==12))
- summary(m)
- m = lm(TotalVol ~ log(ALA) + age + sex + Treatment_OFAMS,df%>%filter(session==24))
- summary(m)
- # 3.3 PASAT -----------------------------------------
- m = lm(PASAT ~ log(ALA),df%>%filter(session==0))
- summary(m)
- m = lm(PASAT ~ log(ALA) + age + sex,df%>%filter(session==0))
- summary(m)
- m = lm(PASAT ~ log(ALA),df%>%filter(session==12))
- summary(m)
- m = lm(PASAT ~ log(ALA) + age + sex + Treatment_OFAMS,df%>%filter(session==12))
- summary(m)
- m = lm(PASAT ~ log(ALA),df%>%filter(session==24))
- summary(m)
- m = lm(PASAT ~ log(ALA) + age + sex + Treatment_OFAMS,df%>%filter(session==24))
- summary(m)
- # 3.4 EDSS -----------------------------------------
- m = lm(edss ~ log(ALA),df%>%filter(session==0))
- summary(m)
- m = lm(edss ~ log(ALA) + DiseaseDuration + sex,df%>%filter(session==0))
- summary(m)
- m = lm(edss ~ log(ALA),df%>%filter(session==12))
- summary(m)
- effectsize::standardize_parameters(m)
- m = lm(edss ~ log(ALA) + DiseaseDuration + sex + Treatment_OFAMS,df%>%filter(session==12))
- summary(m)
- m = lm(edss ~ log(ALA),df%>%filter(session==24))
- summary(m)
- effectsize::standardize_parameters(m)
- m = lm(edss ~ log(ALA) + DiseaseDuration + sex + Treatment_OFAMS,df%>%filter(session==24))
- summary(m)
- effectsize::standardize_parameters(m)
- # 3.5 T1w new Lesions (Negative binomial models) ---------------------
- # BL
- m = glm(new_T1Gd_lesion ~ log(ALA),df%>%filter(session==0),family = binomial(link = cloglog))
- summary(m)
- m = glm(new_T1Gd_lesion ~ log(ALA) +age + sex + Treatment_OFAMS ,df%>%filter(session==0),family = binomial(link = cloglog))
- summary(m)
- # control also for intracranial volume
- m = glm(new_T1Gd_lesion ~ log(ALA) +age + sex + Treatment_OFAMS + EstimatedTotalIntraCranialVol,df%>%filter(session==0),family = binomial(link = cloglog))
- summary(m)
- # 12 months
- m = glm(new_T1Gd_lesion ~ log(ALA),df%>%filter(session==12),family = binomial(link = cloglog))
- summary(m)
- m = glm(new_T1Gd_lesion ~ log(ALA) +age + sex + Treatment_OFAMS ,df%>%filter(session==12),family = binomial(link = cloglog))
- summary(m)
- # control also for intracranial volume
- m = glm(new_T1Gd_lesion ~ log(ALA) +age + sex + Treatment_OFAMS + EstimatedTotalIntraCranialVol,df%>%filter(session==12),family = binomial(link = cloglog))
- summary(m)
- # 24 months
- m = glm(new_T1Gd_lesion ~ log(ALA),df%>%filter(session==24),family = binomial(link = cloglog))
- summary(m)
- m = glm(new_T1Gd_lesion ~ log(ALA) +age + sex + Treatment_OFAMS ,df%>%filter(session==24),family = binomial(link = cloglog))
- summary(m)
- # control also for intracranial volume
- m = glm(new_T1Gd_lesion ~ log(ALA) +age + sex + Treatment_OFAMS + EstimatedTotalIntraCranialVol,df%>%filter(session==24),family = binomial(link = cloglog))
- summary(m)
- # 4. Mediation analyses --------------------------------------
- detach(package:lmerTest,unload = T) # lmerTest needs to leave for these functions to work
- # 4.1 Brain vol > ALA > EDSS----------------------------------
- # select and log transform
- df2 = df %>% dplyr::select(eid,age,sex,DiseaseDuration, Treatment_OFAMS,ALA,edss,TotalVol,lesion_count) #%>% na.omit
- df2$ALA = log(df2$ALA)
- # models
- fit.mediator = lmer(ALA ~ DiseaseDuration + sex + Treatment_OFAMS + TotalVol + (1|eid),df2)
- fit.dv = lmer(edss ~ DiseaseDuration + sex + Treatment_OFAMS + ALA + TotalVol + (1|eid),df2)
- # mediation
- results <- mediation::mediate(fit.mediator, fit.dv, mediator='ALA', treat = 'TotalVol')
- summary(results)
- # 4.2 T1w lesions > ALA > EDSS--------------------------------
- # models
- fit.mediator = lmer(ALA ~ DiseaseDuration + sex + Treatment_OFAMS + lesion_count + (1|eid),df2)
- fit.dv = lmer(edss ~ DiseaseDuration + sex + Treatment_OFAMS + ALA + lesion_count + (1|eid),df2)
- # mediation
- results <- mediation::mediate(fit.mediator, fit.dv, mediator='ALA', treat = 'lesion_count')
- summary(results)
- # 5. Longitudinal predictions of ALA -------------------------
- # prep df
- long.df = merge(df %>% dplyr::filter(session == 0)%>%dplyr::select(eid,ALA,EstimatedTotalIntraCranialVol,Treatment_OFAMS,DiseaseDuration),long, id.vars = "eid")
- # check associations of ALA with THE ANNUAL RATE OF CHANGE in ...
- ## EDSS
- m=lm(EDSS_diff~log(ALA),data=long.df)
- summary(m)
- m=lm(EDSS_diff ~log(ALA)+ DiseaseDuration + sex + Treatment_OFAMS,data=long.df)
- summary(m)
- effectsize::standardize_parameters(m)
- ## PASAT
- m=lm(PASAT_diff~log(ALA),data=long.df)
- summary(m)
- m=lm(PASAT_diff ~log(ALA)+DiseaseDuration + sex + Treatment_OFAMS,data=long.df)
- summary(m)
- ## T2w lesions
- m=lm(lesion_count_diff~log(ALA),data=long.df)
- summary(m)
- m=lm(lesion_count_diff ~log(ALA)+DiseaseDuration + sex + Treatment_OFAMS+EstimatedTotalIntraCranialVol,data=long.df)
- summary(m)
- ## Brain volume
- m=lm(TotalVol_diff~log(ALA),data=long.df)
- summary(m)
- m=lm(TotalVol_diff ~log(ALA)+DiseaseDuration + sex + Treatment_OFAMS+EstimatedTotalIntraCranialVol,data=long.df)
- summary(m)
- ## [[total]] T1w lesions
- m=lm(T1wLesions~log(ALA),data=long.df)
- summary(m)
- m=lm(T1wLesions ~log(ALA)+DiseaseDuration + sex + Treatment_OFAMS+EstimatedTotalIntraCranialVol,data=long.df)
- summary(m)
- ## relapse rate / annual relapses during 12 study years
- m=lm(relapse_rate~log(ALA),data=long.df)
- summary(m)
- effectsize::standardize_parameters(m)
- m=lm(relapse_rate ~log(ALA)+DiseaseDuration + sex + Treatment_OFAMS,data=long.df)
- summary(m)
- effectsize::standardize_parameters(m)
- ## non-log transformed
- m=lm(relapse_rate~(ALA),data=long.df)
- summary(m)
- m=lm(relapse_rate ~(ALA)+DiseaseDuration + sex + Treatment_OFAMS,data=long.df)
- summary(m)
- ## relapse rate / annual relapses during 12 study years + the year before
- m=lm(relapse_rate_prior~log(ALA),data=long.df)
- summary(m)
- m=lm(relapse_rate_prior ~log(ALA)+DiseaseDuration + sex + Treatment_OFAMS,data=long.df)
- summary(m)
- effectsize::standardize_parameters(m)
- ## relapses prior baseline
- m=lm(relapses_12mnths_before_baseline~log(ALA),data=long.df)
- summary(m)
- m=lm(relapses_12mnths_before_baseline ~log(ALA)+DiseaseDuration + sex + Treatment_OFAMS,data=long.df)
- summary(m)
analyse.R at commit dcb02fc, no license · at the source
Overview
- Department of Clinical Medicine, University of Bergen, Bergen, Norway
- Department for Radiography, Western Norway University of Applied Sciences, Bergen, Norway
- Neuro-SysMed, Department of Neurology, Haukeland University Hospital, Bergen, Norway
- Norwegian MS-Registry and Biobank, Helse Bergen, Haukeland University Hospital, Bergen, Norway
- Department of Neurology, St. Olav’s Hospital, Trondheim, Norway
Abstract
Objective: To replicate and extend recent findings, suggesting that higher serum alpha-linolenic acid (ALA) levels are associated with reduced disease activity and progression in multiple sclerosis (MS).
Methods: We reanalysed clinical trial data from 85 people with MS who had serum ALA using magnetic resonance imaging (MRI) and clinical (EDSS, PASAT) assessments, collected for 2 years, with additional follow-up at 12-years. Linear and mixed models were used to assess the relationship between ALA and clinical and MRI outcomes. Mediation analyses tested whether ALA mediated associations between brain volume or T2 lesion load and disability.
Results: ALA measures were consistent over time (κ = 0.83). Higher ALA predicted lower EDSS (β = −0.41, 95% CI [−0.73, −0.08]) and larger brain volume (β = 0.22, 95% CI [0.09, 0.36]). ALA was a non-significant mediator of brain volume or lesion effects on EDSS and did not predict long-term clinical or cognitive changes.
Discussion: We replicate prior associations between higher serum ALA levels and reduced disability in MS and extend these by showing a beneficial association of serum ALA with brain volume. However, ALA did not predict long-term progression, limiting its prognostic value.
Reproduced under the paper's license (CC BY), from the paper cited above.
Repository
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MaxKorbmacher/ALA
dcb02fc4fc1c85ee221d04ddbf15d9b8bce45893, 12 August 2025Availability: 1 check, the latest on 30 September 2026: the link answers
- 30 September 2026: the link answers
4 files
- analyse.R, R, 699 lines, 4 matches
- data_prep.R, R, 119 lines, 1 match
- data_prep_long.R, R, 123 lines
- README.md, Text, 2 lines
The paper's code and data availability statement is in the Data section.
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Data
No dataset and no data link were found in the paper.
Data availability statement
The data analyzed in this study is subject to the following licenses/
Reproduced under the paper's license (CC BY), from the paper cited above.
Versions
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Version 1, 30 September 2026: the first record
Recorded: type, language, journal, volume, pages, dates, 5 authors, 6 keywords, 22 references.
Cite
This paper
Korbmacher, M., Myhr, K.-M., Wergeland, S., Wesnes, K., & Torkildsen, Ø. (2026). Alpha-linolenic acid associations with disability and brain volume in multiple sclerosis: a brief replication report. Frontiers in neurology, 17, 1796427. https://
BibTeX
@article{korbmacher2026a
author = {Korbmacher, Max and Myhr, Kjell-Morten and Wergeland, Stig and Wesnes, Kristin and Torkildsen, Øivind},
title = {{Alpha-linolenic acid associations with disability and brain volume in multiple sclerosis: a brief replication report}},
journal = {Frontiers in neurology},
year = {2026},
month = apr,
volume = {17},
pages = {1796427},
publisher = {Frontiers Media SA},
issn = {1664-2295},
doi = {10.3389/
url = {https://
pmid = {42124854},
pmcid = {PMC13159527}
}
RIS
TY - JOUR
AU - Korbmacher, Max
AU - Myhr, Kjell-Morten
AU - Wergeland, Stig
AU - Wesnes, Kristin
AU - Torkildsen, Øivind
TI - Alpha-linolenic acid associations with disability and brain volume in multiple sclerosis: a brief replication report
T2 - Frontiers in neurology
J2 - Front Neurol
PY - 2026
DA - 2026/
VL - 17
SP - 1796427
SN - 1664-2295
PB - Frontiers Media SA
DO - 10.3389/
UR - https://
LA - en
ER -
CSL-JSON
{
"id": "10.3389/
"type": "article-journal",
"title": "Alpha-linolenic acid associations with disability and brain volume in multiple sclerosis: a brief replication report",
"container-title": "Frontiers in neurology",
"author": [
{
"family": "Korbmacher",
"given": "Max"
},
{
"family": "Myhr",
"given": "Kjell-Morten"
},
{
"family": "Wergeland",
"given": "Stig"
},
{
"family": "Wesnes",
"given": "Kristin"
},
{
"family": "Torkildsen",
"given": "Øivind"
}
],
"container-title-short":
"volume": "17",
"page": "1796427",
"DOI": "10.3389/
"PMID": "42124854",
"PMCID": "PMC13159527",
"ISSN": "1664-2295",
"publisher": "Frontiers Media SA",
"URL": "https://
"language": "en",
"issued": {
"date-parts": [
[
2026,
4,
27
]
]
}
}
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